Is it illegal to do the odd job on the side?

  • KVK Editors
  • Background
  • 28 February 2023
  • Edited 15 September 2025
  • 1 min
  • Rules and laws

Do you make a bit of extra money in the hospitality business, or as a cleaner? Or do you sell home-made cakes, for example, or jewelry? You have to report these extra earnings to the Belastingdienst. If you do not, you are working 'under the table', and you risk a fine.

SBI codes have changed

Many SBI codes were updated in September 2025. Please check whether the description of your business activities is still correct.

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Urban myth about zwartwerken

Doing paid work without reporting it to the Tax Administration is called zwartwerken in Dutch. And, just as in other countries, it is illegal. The idea that you are allowed to earn extra income up to a certain amount is not true. You may work as much as you want, but you have to report your income to the Netherlands Tax Administration (Belastingdienst ). How much tax you have to pay on the extra earnings depends on your personal situation and other income. If you receive a benefit, the amount you earn may affect it. If your income is low (in Dutch), the tax levied on the extra income will be low or none. 

Making extra money and paying taxes

You report the extra money you make as inkomsten uit overige werkzaamheden (income from other activities, in Dutch) in your income tax return. If you have made expenses to earn the extra income, such as travel costs, you may deduct them from this amount. 

If you do not report the extra income you make, and the Tax Administration finds out about it, not only will you have to pay the tax, but you also receive a fine (in Dutch).

Risks of undeclared work

Undeclared work is not without risks. As an undeclared worker, you are not insured. For example, if you have an accident or cause damage. Nor do you build up any rights to benefits. You do not accrue holiday pay, year-end bonus, or pension and you are not protected against dismissal.

Does the Tax Administration catch you working undeclared? Then you could face problems when applying for benefits or social assistance.

Money on the side and registration with KVK

If you only make some extra money occasionally, you do not have to register as a business with KVK. Are you not sure? Contact the KVK Advice Team.

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