INASTI contributionsExpert

5 questions

What are INASTI social contributions?

INASTI (National Institute for the Social Insurance of the Self-Employed) manages social contributions for Belgian self-employed workers. These contributions fund your social protection: pension, family allowances, health insurance and guaranteed income in case of incapacity. As a self-employed person, you must pay them quarterly to your social insurance fund.

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How are my contributions calculated?

Contributions are calculated on your net professional income in three brackets. Bracket 1 up to 75,024.54 EUR is taxed at 20.5%. Bracket 2 from 75,024.54 EUR to 110,562.42 EUR is taxed at 14.16%. Beyond that, no additional contribution is due. A minimum amount applies if your income is low: 3,670.32 EUR per year in 2026 (1,895.36 EUR when starting out).

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What is the INASTI module in Ledgerly?

The INASTI module lets you simulate your contributions based on your estimated income. Enter your expected annual net income and the simulator calculates the annual total, the quarterly amount, and shows which bracket(s) you fall into. It is a cash flow planning tool, not an official calculation from your social fund.

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Do my provisional contributions match my final contributions?

No. You first pay provisional contributions calculated on your income from the previous 3 years. Once your actual income for the year is known (usually 2-3 years later), your social fund carries out a regularisation. If your actual income was higher, you pay a supplement. If it was lower, you get a refund. The Ledgerly simulator helps you anticipate these regularisations.

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Where do I pay my social contributions?

You pay your contributions to your social fund (Acerta, Partena, Xerius, UCM, Securex...) by the last day of each quarter (31 March, 30 June, 30 September, 31 December). Ledgerly does not handle payments directly, it helps you estimate and plan the amounts. To pay, use your online account on your social fund's website.

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