Section

Understand

Updated on 7 October 2026

How net pay is calculated, what is changing, and how Indexo checks its figures. 19 tools and pages, all free, with no sign-up and no cookies.

Understand the calculation

From gross to net: the calculation explainedThe four steps of the calculation, with a typical payslip to the cent.
The net pay curveNet pay by gross pay, from 1,500 to €10,000, and what you keep out of €100 more gross.
The withholding tax key formulaThe statutory withholding tax calculation, step by step, with two examples to the cent.
Your payslip explainedEvery line of a Belgian payslip explained, with its Dutch label and a worked example.
Decode an official documentTax assessment notice, tax form 281.10, holiday pay statement and social contributions notice: every amount explained and checked.
Understand my tax assessment noticeEvery amount in your tax calculation, the tax recalculated by Indexo, and your deadlines for payment and objection.
Tax form 281.10 explainedEvery code on your employer’s tax form, its code in Tax-on-web, and the comparison with a simulated year.
Understanding my holiday pay statement (blue-collar workers)Holiday pay from the ONVA/RJV or the holiday fund, line by line, recalculated from your wages.
Understanding my social contributions noticeThe quarterly self-employed contribution recalculated: reference income, rate, minimum, management fee and adjustment.
Payroll glossaryThe 76 payroll and tax terms defined, with an example, usually the 2026 amount, and the Dutch and French terms.
Frequently asked questionsShort answers, with figures, to the most frequently asked questions.

Salary indexation In seasonThe January 2027 indexation and your sector’s, in net terms, and your purchasing power.
What’s changingWhat changes on 1 January 2027, what has been published or not yet, and your net pay after each change.
Reforms, year by yearThe voted stages of the tax reform, from 2025 to 2031, applied to your salary.
Reform sandboxChange the tax-free amount, the brackets or the work bonus yourself, and see the effect on your net pay.

Method and sourcesThe calculation method, assumptions, limits and the full table of official parameters.
Proof of accuracyCases checked to the cent against payslips and published examples.
Open dataAll calculation parameters in JSON, dated and sourced, reusable.
Useful linksPublic services and support organisations, by situation.

I’m filing my tax returnCheck the proposal, choose between actual expenses and the lump sum, understand the result.
I’m an accountant, HR professional or adviserTools to check, advise and prepare files.