# Bruto netto berekenen loon — Belgium net salary

Source page: https://valem.run/calculators/belgium/net-salary

Your Belgian net salary is gross minus RSZ social security and progressive income tax, after professional costs, the tax-free sum and the municipal surcharge.

**Tax year:** 2025

> **Not yet updated for the current tax year.** Belgium’s July 2026 personal-income-tax reform changed the tax-free sum for 2026 income, and the official FOD Financiën figures could not be retrieved to check against. Until they are, this page computes the rules for 2025 income.

## How it is calculated

Belgian payroll deducts RSZ/ONSS social security of 13.07% from gross, then allows a professional-costs deduction (a 30% forfait, capped) before tax.

Withholding tax is steeply progressive (25% to 50%), reduced by the tax-free sum, with a municipal surcharge of around 7% added on top. The calculator shows the contributions and taxable base. Estimate, not tax advice.

## Worked example

With Bruto jaarloon of 45,000 EUR, this model computes Netto / maand of 2,518.07 EUR.

## Inputs

| Name | Label | Type |
| --- | --- | --- |
| `grossAnnual` | Bruto jaarloon | number |

## Sources

- [FOD Financiën Tax-Calc](https://financien.belgium.be) (checked 2026-08-02)
- [RSZ](https://www.socialsecurity.be) (checked 2026-08-02)

## What this page claims

The Valem engine reproduces this model's formula through 2 self-test cases. That shows internal consistency, not that the formula matches current law; the cited sources are the evidence for that. Estimate, not tax advice.

## For agents

- Model manifest (formula, constants, test vectors): https://valem.run/calculators/belgium/net-salary.json
- Compute by URL: https://valem.run/calculators/belgium/net-salary.json?grossAnnual=45000
- MCP: https://valem.run/mcp/calculators (call `calculate` with calculator `belgium/net-salary`)