{
  "$comment": "Machine-readable companion to https://valem.run/calculators/tools/rent-vs-buy. Formula, inputs, outputs, engine-verified test vectors, cited sources and the re-runnable Valem ModelSpec behind the page.",
  "url": "https://valem.run/calculators/tools/rent-vs-buy",
  "dataUrl": "https://valem.run/calculators/tools/rent-vs-buy.json",
  "license": {
    "name": "CC BY 4.0",
    "url": "https://creativecommons.org/licenses/by/4.0/",
    "attribution": "Decision tools rent vs buy model by Valem (https://valem.run/calculators/tools/rent-vs-buy), CC BY 4.0.",
    "note": "Covers the model — the expression of each rule and the arrangement of the catalog. The rates and thresholds themselves are law and are not licensed by anyone; the cited sources are where they come from."
  },
  "verificationUrl": "https://valem.run/calculators/tools/rent-vs-buy/verify",
  "country": "tools",
  "countryName": "Decision tools",
  "formula": "rent-vs-buy",
  "formulaName": "Rent vs buy",
  "title": "Rent vs Buy Calculator",
  "answer": "Buying beats renting once the equity you build plus house price growth outweighs the return the same money would have earned invested — which depends on how long you stay, and typically takes well over a decade at ordinary appreciation and investment returns.",
  "lang": "en",
  "currency": "USD",
  "taxYear": "",
  "verification": {
    "claim": "internal-consistency",
    "statement": "The Valem engine reproduces this model's stated formula through 3 self-test cases (below, and re-runnable against the spec). That asserts internal consistency, NOT that the formula matches current law — the cited sources are the evidence for that, and carry the date each was last checked.",
    "selfTestCases": 3,
    "ratesAreIllustrative": false,
    "sourcesCheckedOn": "2026-08-02"
  },
  "sources": [],
  "terminalOutput": "favoursBuying",
  "inputs": [
    {
      "name": "homePrice",
      "type": "number",
      "label": "House price",
      "minimum": 0
    },
    {
      "name": "depositPct",
      "type": "number",
      "label": "Deposit (%)",
      "minimum": 0,
      "maximum": 100
    },
    {
      "name": "mortgageRatePct",
      "type": "number",
      "label": "Mortgage rate (%)",
      "minimum": 0,
      "maximum": 25
    },
    {
      "name": "mortgageTermYears",
      "type": "integer",
      "label": "Mortgage term (years)",
      "minimum": 1,
      "maximum": 40
    },
    {
      "name": "closingCostsPct",
      "type": "number",
      "label": "Buying costs (% of price)",
      "minimum": 0,
      "maximum": 20
    },
    {
      "name": "sellingCostsPct",
      "type": "number",
      "label": "Selling costs (% of value)",
      "minimum": 0,
      "maximum": 20
    },
    {
      "name": "propertyTaxPct",
      "type": "number",
      "label": "Property tax (% of value / yr)",
      "minimum": 0,
      "maximum": 10
    },
    {
      "name": "insurancePerYear",
      "type": "number",
      "label": "Buildings insurance / yr",
      "minimum": 0
    },
    {
      "name": "maintenancePct",
      "type": "number",
      "label": "Maintenance (% of value / yr)",
      "minimum": 0,
      "maximum": 10
    },
    {
      "name": "hoaPerMonth",
      "type": "number",
      "label": "Service charge / month",
      "minimum": 0
    },
    {
      "name": "appreciationPct",
      "type": "number",
      "label": "House price growth per year (%)",
      "minimum": -10,
      "maximum": 20
    },
    {
      "name": "taxReliefPct",
      "type": "number",
      "label": "Mortgage interest tax relief (%)",
      "minimum": 0,
      "maximum": 100
    },
    {
      "name": "monthlyRent",
      "type": "number",
      "label": "Rent / month",
      "minimum": 0
    },
    {
      "name": "rentInflationPct",
      "type": "number",
      "label": "Rent rises per year (%)",
      "minimum": -10,
      "maximum": 20
    },
    {
      "name": "rentersInsurancePerYear",
      "type": "number",
      "label": "Contents insurance / yr",
      "minimum": 0
    },
    {
      "name": "investmentReturnPct",
      "type": "number",
      "label": "Investment return the renter earns (%)",
      "minimum": 0,
      "maximum": 20
    },
    {
      "name": "years",
      "type": "integer",
      "label": "Years you stay",
      "minimum": 1,
      "maximum": 40
    }
  ],
  "outputs": [
    {
      "name": "deposit",
      "type": "number",
      "formula": "$round(homePrice * depositPct / 100, 2)"
    },
    {
      "name": "loanAmount",
      "type": "number",
      "formula": "$round(homePrice - deposit, 2)"
    },
    {
      "name": "closingCosts",
      "type": "number",
      "formula": "$round(homePrice * closingCostsPct / 100, 2)"
    },
    {
      "name": "monthlyRate",
      "type": "number",
      "formula": "mortgageRatePct / 1200"
    },
    {
      "name": "compoundFactor",
      "type": "number",
      "formula": "$power(1 + monthlyRate, mortgageTermYears * 12)"
    },
    {
      "name": "monthlyPayment",
      "type": "number",
      "formula": "loanAmount <= 0 ? 0 : (monthlyRate = 0 ? $round(loanAmount / (mortgageTermYears * 12), 2) : $round(loanAmount * monthlyRate * compoundFactor / (compoundFactor - 1), 2))"
    },
    {
      "name": "comparison",
      "type": "array",
      "label": "Net worth on each path",
      "formula": "( $r := $reduce([1..years], function($a, $y) { ( $term := mortgageTermYears * 12; $hv := $round(homePrice * $power(1 + appreciationPct / 100, $y), 2); $hvPrev := $round(homePrice * $power(1 + appreciationPct / 100, $y - 1), 2); $m1 := $min([($y - 1) * 12, $term]); $m2 := $min([$y * 12, $term]); $b1 := $balanceAt($m1, loanAmount, monthlyRate, compoundFactor, $term); $b2 := $balanceAt($m2, loanAmount, monthlyRate, compoundFactor, $term); $interest := $max([0, $round(monthlyPayment * ($m2 - $m1) - ($b1 - $b2), 2)]); $relief := $round($interest * taxReliefPct / 100, 2); $principal := $round($b1 - $b2, 2); $carry := $round($interest - $relief + $hvPrev * propertyTaxPct / 100 + $hvPrev * maintenancePct / 100 + insurancePerYear + hoaPerMonth * 12, 2); $outlay := $round($carry + $principal, 2); $rentYear := $round(monthlyRent * 12 * $power(1 + rentInflationPct / 100, $y - 1) + rentersInsurancePerYear, 2); $invested := $round($outlay - $rentYear, 2); $port := $round(($a.portfolio + $invested) * (1 + investmentReturnPct / 100), 2); { \"portfolio\": $port, \"rows\": $append($a.rows, [{ \"year\": $y, \"homeValue\": $hv, \"mortgageBalance\": $b2, \"buyCost\": $carry, \"rentCost\": $rentYear, \"buyNet\": $round($hv - $b2 - $hv * sellingCostsPct / 100, 2), \"rentNet\": $port }]) } ) }, { \"portfolio\": $round(deposit + closingCosts, 2), \"rows\": [] }); [$r.rows] )"
    },
    {
      "name": "breakevenYear",
      "type": "integer",
      "label": "Buying pulls ahead in year",
      "format": "number",
      "formula": "( $hits := $map(comparison, function($c) { $c.buyNet >= $c.rentNet ? $c.year : 0 })[$ > 0]; $count($hits) = 0 ? 0 : $min($hits) )"
    },
    {
      "name": "totalBuyCost",
      "type": "number",
      "label": "Total cost of owning",
      "format": "number",
      "formula": "$round($sum($map(comparison, function($c) { $c.buyCost })), 2)"
    },
    {
      "name": "totalRentCost",
      "type": "number",
      "label": "Total rent paid",
      "format": "number",
      "formula": "$round($sum($map(comparison, function($c) { $c.rentCost })), 2)"
    },
    {
      "name": "netAdvantage",
      "type": "number",
      "label": "Net worth difference",
      "format": "number",
      "formula": "( $d := $map(comparison, function($c) { $round($c.buyNet - $c.rentNet, 2) }); $i := $count($d) - 1; $d[$i] )"
    },
    {
      "name": "favoursBuying",
      "type": "boolean",
      "formula": "netAdvantage >= 0"
    }
  ],
  "testCases": [
    {
      "description": "400,000 home at 6.5% with 20% down vs 2,200 rent, 3% appreciation, 7% return, staying 20 years",
      "given": {
        "homePrice": 400000,
        "depositPct": 20,
        "mortgageRatePct": 6.5,
        "monthlyRent": 2200,
        "appreciationPct": 3,
        "investmentReturnPct": 7,
        "years": 20
      },
      "expect": {
        "deposit": 80000,
        "closingCosts": 12000,
        "loanAmount": 320000,
        "monthlyPayment": 2022.62,
        "comparison[0].homeValue": 412000,
        "comparison[0].mortgageBalance": 316423.28,
        "comparison[0].buyNet": 70856.72,
        "comparison[0].rentNet": 106220.44,
        "comparison[19].buyNet": 500968.92,
        "comparison[19].rentNet": 470936.57,
        "totalBuyCost": 593268.83,
        "totalRentCost": 713377.88,
        "breakevenYear": 16,
        "netAdvantage": 30032.35,
        "favoursBuying": true
      }
    },
    {
      "description": "the same move over only 8 years — renting and investing the difference wins, and there is no breakeven",
      "given": {
        "years": 8
      },
      "expect": {
        "comparison[7].buyNet": 192604.18,
        "comparison[7].rentNet": 218145.84,
        "breakevenYear": 0,
        "netAdvantage": -25541.66,
        "favoursBuying": false
      }
    },
    {
      "description": "no appreciation, no investment return, no rent rises — the pure cash comparison you can check by hand",
      "given": {
        "appreciationPct": 0,
        "investmentReturnPct": 0,
        "rentInflationPct": 0,
        "years": 5
      },
      "expect": {
        "comparison[0].homeValue": 400000,
        "comparison[0].buyNet": 59576.72,
        "comparison[0].rentNet": 99271.44,
        "comparison[4].homeValue": 400000,
        "totalRentCost": 133000,
        "totalBuyCost": 148912.33,
        "breakevenYear": 0,
        "netAdvantage": -51912.33
      }
    }
  ],
  "spec": {
    "id": "rent-vs-buy",
    "version": "1.0.0",
    "schema": {
      "type": "object",
      "properties": {
        "homePrice": {
          "type": "number",
          "minimum": 0
        },
        "depositPct": {
          "type": "number",
          "minimum": 0,
          "maximum": 100,
          "description": "Down payment as a percent of the price"
        },
        "mortgageRatePct": {
          "type": "number",
          "minimum": 0,
          "maximum": 25
        },
        "mortgageTermYears": {
          "type": "integer",
          "minimum": 1,
          "maximum": 40
        },
        "closingCostsPct": {
          "type": "number",
          "minimum": 0,
          "maximum": 20,
          "description": "One-off costs of buying, percent of price"
        },
        "sellingCostsPct": {
          "type": "number",
          "minimum": 0,
          "maximum": 20,
          "description": "Agent and legal fees on sale, percent of value"
        },
        "propertyTaxPct": {
          "type": "number",
          "minimum": 0,
          "maximum": 10,
          "description": "Annual property tax, percent of value"
        },
        "insurancePerYear": {
          "type": "number",
          "minimum": 0
        },
        "maintenancePct": {
          "type": "number",
          "minimum": 0,
          "maximum": 10,
          "description": "Annual upkeep, percent of value"
        },
        "hoaPerMonth": {
          "type": "number",
          "minimum": 0,
          "description": "Service charge / HOA / ground rent"
        },
        "appreciationPct": {
          "type": "number",
          "minimum": -10,
          "maximum": 20,
          "description": "Assumed house price growth per year"
        },
        "taxReliefPct": {
          "type": "number",
          "minimum": 0,
          "maximum": 100,
          "description": "Share of mortgage interest you get back in tax relief (0 where there is none)"
        },
        "monthlyRent": {
          "type": "number",
          "minimum": 0
        },
        "rentInflationPct": {
          "type": "number",
          "minimum": -10,
          "maximum": 20
        },
        "rentersInsurancePerYear": {
          "type": "number",
          "minimum": 0
        },
        "investmentReturnPct": {
          "type": "number",
          "minimum": 0,
          "maximum": 20,
          "description": "What the renter earns on the money not tied up in a house"
        },
        "years": {
          "type": "integer",
          "minimum": 1,
          "maximum": 40,
          "description": "How long you stay"
        },
        "deposit": {
          "type": "number",
          "readOnly": true
        },
        "loanAmount": {
          "type": "number",
          "readOnly": true
        },
        "closingCosts": {
          "type": "number",
          "readOnly": true
        },
        "monthlyRate": {
          "type": "number",
          "readOnly": true
        },
        "compoundFactor": {
          "type": "number",
          "readOnly": true
        },
        "monthlyPayment": {
          "type": "number",
          "readOnly": true
        },
        "comparison": {
          "type": "array",
          "readOnly": true,
          "items": {
            "type": "object",
            "properties": {
              "year": {
                "type": "integer"
              },
              "homeValue": {
                "type": "number"
              },
              "mortgageBalance": {
                "type": "number"
              },
              "buyCost": {
                "type": "number"
              },
              "rentCost": {
                "type": "number"
              },
              "buyNet": {
                "type": "number"
              },
              "rentNet": {
                "type": "number"
              }
            }
          }
        },
        "breakevenYear": {
          "type": "integer",
          "readOnly": true,
          "description": "First year buying is ahead; 0 when it never is inside the horizon"
        },
        "totalBuyCost": {
          "type": "number",
          "readOnly": true
        },
        "totalRentCost": {
          "type": "number",
          "readOnly": true
        },
        "netAdvantage": {
          "type": "number",
          "readOnly": true,
          "description": "Buyer net worth minus renter net worth in the final year"
        },
        "favoursBuying": {
          "type": "boolean",
          "readOnly": true
        }
      },
      "required": [
        "homePrice",
        "monthlyRent",
        "years"
      ]
    },
    "library": {
      "layers": [
        {
          "define": "( $balanceAt := function($m, $principal, $rate, $factor, $term) { ($term <= 0 or $principal <= 0) ? 0 : ($rate = 0 ? $principal * (1 - $m / $term) : $round($principal * ($factor - $power(1 + $rate, $m)) / ($factor - 1), 2)) }; [\"balanceAt\"] )"
        }
      ]
    },
    "defaultValues": [
      {
        "path": "$",
        "expr": "{\"homePrice\": 400000, \"depositPct\": 20, \"mortgageRatePct\": 6.5, \"mortgageTermYears\": 30, \"closingCostsPct\": 3, \"sellingCostsPct\": 6, \"propertyTaxPct\": 1.1, \"insurancePerYear\": 1200, \"maintenancePct\": 1, \"hoaPerMonth\": 0, \"appreciationPct\": 3, \"taxReliefPct\": 0, \"monthlyRent\": 2200, \"rentInflationPct\": 3, \"rentersInsurancePerYear\": 200, \"investmentReturnPct\": 7, \"years\": 20}"
      }
    ],
    "derivations": [
      {
        "path": "$.deposit",
        "expr": "$round(homePrice * depositPct / 100, 2)"
      },
      {
        "path": "$.closingCosts",
        "expr": "$round(homePrice * closingCostsPct / 100, 2)"
      },
      {
        "path": "$.monthlyRate",
        "expr": "mortgageRatePct / 1200"
      },
      {
        "path": "$.loanAmount",
        "expr": "$round(homePrice - deposit, 2)"
      },
      {
        "path": "$.compoundFactor",
        "expr": "$power(1 + monthlyRate, mortgageTermYears * 12)"
      },
      {
        "path": "$.monthlyPayment",
        "expr": "loanAmount <= 0 ? 0 : (monthlyRate = 0 ? $round(loanAmount / (mortgageTermYears * 12), 2) : $round(loanAmount * monthlyRate * compoundFactor / (compoundFactor - 1), 2))"
      },
      {
        "path": "$.comparison",
        "expr": "( $r := $reduce([1..years], function($a, $y) { ( $term := mortgageTermYears * 12; $hv := $round(homePrice * $power(1 + appreciationPct / 100, $y), 2); $hvPrev := $round(homePrice * $power(1 + appreciationPct / 100, $y - 1), 2); $m1 := $min([($y - 1) * 12, $term]); $m2 := $min([$y * 12, $term]); $b1 := $balanceAt($m1, loanAmount, monthlyRate, compoundFactor, $term); $b2 := $balanceAt($m2, loanAmount, monthlyRate, compoundFactor, $term); $interest := $max([0, $round(monthlyPayment * ($m2 - $m1) - ($b1 - $b2), 2)]); $relief := $round($interest * taxReliefPct / 100, 2); $principal := $round($b1 - $b2, 2); $carry := $round($interest - $relief + $hvPrev * propertyTaxPct / 100 + $hvPrev * maintenancePct / 100 + insurancePerYear + hoaPerMonth * 12, 2); $outlay := $round($carry + $principal, 2); $rentYear := $round(monthlyRent * 12 * $power(1 + rentInflationPct / 100, $y - 1) + rentersInsurancePerYear, 2); $invested := $round($outlay - $rentYear, 2); $port := $round(($a.portfolio + $invested) * (1 + investmentReturnPct / 100), 2); { \"portfolio\": $port, \"rows\": $append($a.rows, [{ \"year\": $y, \"homeValue\": $hv, \"mortgageBalance\": $b2, \"buyCost\": $carry, \"rentCost\": $rentYear, \"buyNet\": $round($hv - $b2 - $hv * sellingCostsPct / 100, 2), \"rentNet\": $port }]) } ) }, { \"portfolio\": $round(deposit + closingCosts, 2), \"rows\": [] }); [$r.rows] )"
      },
      {
        "path": "$.totalBuyCost",
        "expr": "$round($sum($map(comparison, function($c) { $c.buyCost })), 2)"
      },
      {
        "path": "$.totalRentCost",
        "expr": "$round($sum($map(comparison, function($c) { $c.rentCost })), 2)"
      },
      {
        "path": "$.breakevenYear",
        "expr": "( $hits := $map(comparison, function($c) { $c.buyNet >= $c.rentNet ? $c.year : 0 })[$ > 0]; $count($hits) = 0 ? 0 : $min($hits) )"
      },
      {
        "path": "$.netAdvantage",
        "expr": "( $d := $map(comparison, function($c) { $round($c.buyNet - $c.rentNet, 2) }); $i := $count($d) - 1; $d[$i] )"
      },
      {
        "path": "$.favoursBuying",
        "expr": "netAdvantage >= 0"
      }
    ],
    "constraints": [
      {
        "id": "price-positive",
        "expr": "homePrice > 0",
        "message": "House price must be positive",
        "policy": "rollback"
      },
      {
        "id": "rent-positive",
        "expr": "monthlyRent > 0",
        "message": "Monthly rent must be positive — this compares two real options",
        "policy": "rollback"
      },
      {
        "id": "rate-positive",
        "expr": "mortgageRatePct > 0",
        "message": "Mortgage rate must be positive",
        "policy": "rollback"
      },
      {
        "id": "stay-within-term",
        "expr": "years <= mortgageTermYears",
        "message": "You are staying longer than the mortgage term — the comparison stops at the end of the term",
        "policy": "flag"
      }
    ],
    "viewDefinition": {
      "renderer": "builtin",
      "defaultView": "main",
      "views": [
        {
          "id": "main",
          "label": "Rent vs buy",
          "layout": "vertical",
          "components": [
            {
              "id": "assumptions",
              "type": "alert",
              "variant": "info",
              "label": "This is a projection from your assumptions",
              "text": "The answer is decided by two guesses nobody can make for you: how fast houses appreciate and what the renter earns on the money not tied up in a deposit. Both are inputs below, and both are visible on purpose — a calculator that hides them is hiding the answer. Not financial advice."
            },
            {
              "id": "buySet",
              "type": "fieldSet",
              "legend": "Buying",
              "components": [
                {
                  "id": "priceField",
                  "type": "numericField",
                  "label": "House price",
                  "bind": "$.homePrice",
                  "placeholder": "400000"
                },
                {
                  "id": "depositField",
                  "type": "sliderField",
                  "label": "Deposit (%)",
                  "bind": "$.depositPct",
                  "min": 0,
                  "max": 100,
                  "step": 1
                },
                {
                  "id": "rateField",
                  "type": "numericField",
                  "label": "Mortgage rate (%)",
                  "bind": "$.mortgageRatePct",
                  "placeholder": "6.5"
                },
                {
                  "id": "termField",
                  "type": "numericField",
                  "label": "Mortgage term (years)",
                  "bind": "$.mortgageTermYears",
                  "placeholder": "30"
                },
                {
                  "id": "closingField",
                  "type": "numericField",
                  "label": "Buying costs (% of price)",
                  "bind": "$.closingCostsPct",
                  "placeholder": "3"
                },
                {
                  "id": "sellingField",
                  "type": "numericField",
                  "label": "Selling costs (% of value)",
                  "bind": "$.sellingCostsPct",
                  "placeholder": "6"
                },
                {
                  "id": "taxField",
                  "type": "numericField",
                  "label": "Property tax (% of value / yr)",
                  "bind": "$.propertyTaxPct",
                  "placeholder": "1.1"
                },
                {
                  "id": "insuranceField",
                  "type": "numericField",
                  "label": "Buildings insurance / yr",
                  "bind": "$.insurancePerYear",
                  "placeholder": "1200"
                },
                {
                  "id": "maintField",
                  "type": "numericField",
                  "label": "Maintenance (% of value / yr)",
                  "bind": "$.maintenancePct",
                  "placeholder": "1"
                },
                {
                  "id": "hoaField",
                  "type": "numericField",
                  "label": "Service charge / month",
                  "bind": "$.hoaPerMonth",
                  "placeholder": "0"
                },
                {
                  "id": "reliefField",
                  "type": "numericField",
                  "label": "Mortgage interest tax relief (%)",
                  "bind": "$.taxReliefPct",
                  "placeholder": "0"
                }
              ]
            },
            {
              "id": "rentSet",
              "type": "fieldSet",
              "legend": "Renting",
              "components": [
                {
                  "id": "rentField",
                  "type": "numericField",
                  "label": "Rent / month",
                  "bind": "$.monthlyRent",
                  "placeholder": "2200"
                },
                {
                  "id": "rentInflationField",
                  "type": "numericField",
                  "label": "Rent rises per year (%)",
                  "bind": "$.rentInflationPct",
                  "placeholder": "3"
                },
                {
                  "id": "contentsField",
                  "type": "numericField",
                  "label": "Contents insurance / yr",
                  "bind": "$.rentersInsurancePerYear",
                  "placeholder": "200"
                }
              ]
            },
            {
              "id": "sharedSet",
              "type": "fieldSet",
              "legend": "The two assumptions that decide it",
              "components": [
                {
                  "id": "apprField",
                  "type": "sliderField",
                  "label": "House price growth per year (%)",
                  "bind": "$.appreciationPct",
                  "min": -5,
                  "max": 12,
                  "step": 0.5
                },
                {
                  "id": "returnField",
                  "type": "sliderField",
                  "label": "Investment return the renter earns (%)",
                  "bind": "$.investmentReturnPct",
                  "min": 0,
                  "max": 15,
                  "step": 0.5
                },
                {
                  "id": "yearsField",
                  "type": "sliderField",
                  "label": "Years you stay",
                  "bind": "$.years",
                  "min": 1,
                  "max": 40,
                  "step": 1
                }
              ]
            },
            {
              "id": "sep1",
              "type": "separatorLine"
            },
            {
              "id": "headline",
              "type": "group",
              "layout": "horizontal",
              "components": [
                {
                  "id": "breakevenTile",
                  "type": "statTile",
                  "label": "Buying pulls ahead in year",
                  "bind": "$.breakevenYear",
                  "format": "number",
                  "caption": "0 means it never does inside your horizon"
                },
                {
                  "id": "advantageTile",
                  "type": "statTile",
                  "label": "Net worth difference",
                  "bind": "$.netAdvantage",
                  "format": "number",
                  "caption": "buyer minus renter, final year"
                },
                {
                  "id": "buyCostTile",
                  "type": "statTile",
                  "label": "Total cost of owning",
                  "bind": "$.totalBuyCost",
                  "format": "number",
                  "caption": "interest, tax, upkeep — not principal"
                },
                {
                  "id": "rentCostTile",
                  "type": "statTile",
                  "label": "Total rent paid",
                  "bind": "$.totalRentCost",
                  "format": "number"
                }
              ]
            },
            {
              "id": "verdict",
              "type": "alert",
              "variant": "info",
              "label": "On these assumptions",
              "text": "favoursBuying ? 'Buying leaves you better off by the year you move out.' : 'Renting and investing the difference leaves you better off over this period.'"
            },
            {
              "id": "sep2",
              "type": "separatorLine"
            },
            {
              "id": "crossoverChart",
              "type": "dataChart",
              "label": "Net worth on each path",
              "chartType": "line",
              "bind": "$.comparison",
              "chartX": "year",
              "chartSeries": [
                {
                  "field": "buyNet",
                  "label": "Buying (equity after selling costs)"
                },
                {
                  "field": "rentNet",
                  "label": "Renting (invested difference)"
                }
              ]
            },
            {
              "id": "comparisonTable",
              "type": "dataTable",
              "label": "Year by year",
              "bind": "$.comparison",
              "tableColumns": [
                {
                  "field": "year",
                  "header": "Year",
                  "width": "8%"
                },
                {
                  "field": "homeValue",
                  "header": "House value",
                  "format": "number",
                  "width": "16%"
                },
                {
                  "field": "mortgageBalance",
                  "header": "Mortgage left",
                  "format": "number",
                  "width": "16%"
                },
                {
                  "field": "buyCost",
                  "header": "Cost of owning",
                  "format": "number",
                  "width": "15%"
                },
                {
                  "field": "rentCost",
                  "header": "Rent paid",
                  "format": "number",
                  "width": "15%"
                },
                {
                  "field": "buyNet",
                  "header": "Buyer net worth",
                  "format": "number",
                  "width": "15%"
                },
                {
                  "field": "rentNet",
                  "header": "Renter net worth",
                  "format": "number",
                  "width": "15%"
                }
              ],
              "pageSize": 15
            }
          ]
        }
      ]
    },
    "tests": [
      {
        "description": "400,000 home at 6.5% with 20% down vs 2,200 rent, 3% appreciation, 7% return, staying 20 years",
        "given": {
          "$.homePrice": 400000,
          "$.depositPct": 20,
          "$.mortgageRatePct": 6.5,
          "$.monthlyRent": 2200,
          "$.appreciationPct": 3,
          "$.investmentReturnPct": 7,
          "$.years": 20
        },
        "expect": {
          "$.deposit": 80000,
          "$.closingCosts": 12000,
          "$.loanAmount": 320000,
          "$.monthlyPayment": 2022.62,
          "$.comparison[0].homeValue": 412000,
          "$.comparison[0].mortgageBalance": 316423.28,
          "$.comparison[0].buyNet": 70856.72,
          "$.comparison[0].rentNet": 106220.44,
          "$.comparison[19].buyNet": 500968.92,
          "$.comparison[19].rentNet": 470936.57,
          "$.totalBuyCost": 593268.83,
          "$.totalRentCost": 713377.88,
          "$.breakevenYear": 16,
          "$.netAdvantage": 30032.35,
          "$.favoursBuying": true
        }
      },
      {
        "description": "the same move over only 8 years — renting and investing the difference wins, and there is no breakeven",
        "given": {
          "$.years": 8
        },
        "expect": {
          "$.comparison[7].buyNet": 192604.18,
          "$.comparison[7].rentNet": 218145.84,
          "$.breakevenYear": 0,
          "$.netAdvantage": -25541.66,
          "$.favoursBuying": false
        }
      },
      {
        "description": "no appreciation, no investment return, no rent rises — the pure cash comparison you can check by hand",
        "given": {
          "$.appreciationPct": 0,
          "$.investmentReturnPct": 0,
          "$.rentInflationPct": 0,
          "$.years": 5
        },
        "expect": {
          "$.comparison[0].homeValue": 400000,
          "$.comparison[0].buyNet": 59576.72,
          "$.comparison[0].rentNet": 99271.44,
          "$.comparison[4].homeValue": 400000,
          "$.totalRentCost": 133000,
          "$.totalBuyCost": 148912.33,
          "$.breakevenYear": 0,
          "$.netAdvantage": -51912.33
        }
      }
    ]
  }
}