The expressions above read these as $const. They are the figures the annual refresh replaces, so they live as data rather than being written into the formulas — which is what makes a year-on-year change a one-line diff instead of an edit to arithmetic.
Constant
Value
standardRate
0.05
hstOntario
0.13
hstNovaScotia
0.14
hstParticipating
0.15
Test vectors (6)
Every case is executed against this model on each build, by the Java engine and independently by a JavaScript one. A mismatch of a single cent fails the build, so the page cannot ship advertising a figure the model no longer produces.
Case 1 — S1 100.00 CAD net in a non-participating province: 5% GST
given amount
100
given direction
add
given category
standard
given reverseCharge
no
expect vatAmount
5
expect grossAmount
105
expect netAmount
100
Case 2 — S2 100.00 CAD in Ontario: 13% HST
given amount
100
given direction
add
given category
ontario
given reverseCharge
no
expect vatAmount
13
expect grossAmount
113
Case 3 — S3 100.00 CAD in Nova Scotia: 14% HST since 1 April 2025
given amount
100
given direction
add
given category
novaScotia
given reverseCharge
no
expect rate
0.14
expect vatAmount
14
expect grossAmount
114
Case 4 — S4 100.00 CAD in another participating province: 15% HST
given amount
100
given direction
add
given category
participating
given reverseCharge
no
expect vatAmount
15
expect grossAmount
115
Case 5 — S5 113.00 CAD gross in Ontario back to net
given amount
113
given direction
remove
given category
ontario
given reverseCharge
no
expect netAmount
100
expect vatAmount
13
Case 6 — S6 reverse charge: the supplier charges no GST/HST
The whole model as JSON — inputs, outputs, formulas, vectors and sources in one re-runnable document.
This model is published under CC BY 4.0: use it, adapt it, build on it, with attribution. The licence covers the model — the expression of each rule and the arrangement of the catalog. The rates and thresholds are law, and nobody licenses those; the sources above are where they come from.