Investing involves risk of loss. Prices can fluctuate and you can lose your invested capital. Product risks vary by instrument and product structure. This is not investment advice. We explain how products and costs work; we do not tell you what to buy. Tax treatment depends on your individual circumstances and may change. Please consult a tax adviser. Fees and conditions change; the provider's own fee schedule and documents prevail.
In this guide
Side income does not need to be complicated, but the framework matters, and for expats there are a few layers on top of the standard Dutch rules. This guide covers the legal framework, the tax rules, side hustle ideas and how passive income from investments fits in.
đź’ˇ Looking for a complete banking comparison? Read Best banking for expats in the Netherlands 2026.
Quick answer: Extra income is usually taxable in box 1. Regular, commercial work may need KvK registration, and if your residence permit limits the work you may do, check with the IND before you start. Investments are taxed in box 3 on a deemed return.
The Legal Framework: Bijverdienste vs ZZP
Bijverdienste: small supplementary earnings
Bijverdienste (earning on the side) refers to small, occasional income that is not a business, for example selling your own second-hand items. Such income may still have to be declared (overige werkzaamheden), but it does not by itself mean you run a business.
The grey zone: there is no euro threshold below which income is automatically bijverdienste. What matters is whether your activity is commercial: you offer services to customers, you repeat the activity and you aim to make a profit. If you are unsure, ask the Belastingdienst or the KvK.
ZZP: registered self-employment
If your side income becomes regular and commercial, you register as a ZZP (zelfstandige zonder personeel) at the KvK. The one-time KvK registration costs €85.15 (2026).
After registration:
- you receive a KvK number, and the Belastingdienst decides whether you are an entrepreneur for VAT; if so you usually receive your VAT number usually within two weeks of registering;
- you issue invoices to clients and file VAT returns, unless you use the small business scheme;
- your profit is declared in your annual income tax return in box 1.
The KOR (kleineondernemersregeling): you can use it if you are established in the Netherlands and have no more than EUR 20,000 turnover in one calendar year. With the KOR you do not charge VAT. As soon as turnover goes above EUR 20,000 in a calendar year you must deregister immediately (Belastingdienst).
Tax Rules
Box 1 rates (2026)
Profit is added to your other box 1 income. For people below AOW age the rates in 2026 are (Belastingdienst):
| Income bracket | Rate |
|---|---|
| Up to EUR 38,883 | 35.75% |
| EUR 38,883 to EUR 78,426 | 37.56% |
| Above EUR 78,426 | 49.50% |
If your salary already puts you in the top band, extra profit is taxed at 49.50%. Example: EUR 5,000 of profit on top of EUR 90,000 of salary is taxed at 49.50%, which is EUR 2,475 of tax and EUR 2,525 after tax. Income taxed in a lower band is taxed at that band’s rate.
Business deductions
If you are an entrepreneur for income tax and you meet the hours criterion (urencriterium), you can use:
- Zelfstandigenaftrek: EUR 1,200 in 2026, with a limited tax benefit in 2026 (Belastingdienst);
- Startersaftrek: EUR 2,123 on top of the zelfstandigenaftrek for qualifying starters;
- MKB-winstvrijstelling: 12.7% of profit after entrepreneur deductions in 2025 and 2026.
The hours criterion is at least 1,225 hours a year on your business, and more time on the business than on other work such as employment, with an exception if you were not an entrepreneur in one of the 5 preceding years (Belastingdienst). For many people with a full-time job it is hard to meet. If you do not meet it, the profit is generally declared as overige werkzaamheden without these deductions.
Keep your records and receipts. Ask the Belastingdienst or an adviser which expenses are deductible in your case.
The 30% ruling and side income
The 30% ruling relates to your salary from the employer that applied for it. Check the Belastingdienst’s conditions for how other income is treated, and ask a tax adviser about your own case.
Residence Permit Restrictions
This section matters for non-EU expats. Some residence permits limit the work you may do. The IND says that your permit shows whether you may work as an employee, for example by the note that work as an employee is only allowed with a work permit (TWV). A highly skilled migrant permit is tied to a recognised sponsor.
Before you start paid work outside your main employment, or register as a ZZP:
- check the conditions of your permit;
- ask your employer’s HR or immigration adviser;
- consult the IND directly or use a registered immigration adviser.
EU citizens do not need a work permit. If you have questions about your specific permit, read our guide to the highly skilled migrant visa.
Side Hustle Options for Expats
These are ideas, not rankings. We do not publish income figures because we have no measured source for them.
- Freelance work in your professional field. If you are a developer, designer, consultant, marketer, translator or financial professional, you can offer your skills as a freelancer. Many professional services operate in English.
- English tutoring. Platforms such as Preply let you offer lessons online. Check the platform’s own terms and commission before you sign up.
- Writing, editing and translation. Useful if you have a strong command of English and another language.
- Digital products and online courses. Take time to build and can then be sold repeatedly.
- Selling second-hand goods. Marktplaats is a Dutch marketplace for second-hand items. If you resell goods regularly to make a profit, it may count as a business.
- Photography and video. Event, product and real estate photography for local businesses.
- Renting out a room. See the kamerverhuurvrijstelling in the FAQ above. Check that your rental contract or mortgage terms allow subletting.
Passive Income: What the Tax Rules Say
True passive income is limited. Returns on investments are never guaranteed, and you can get back less than you put in.
ETFs and index funds (box 3)
Investing through a broker such as DEGIRO is sometimes described as passive income. Investments fall under box 3, which taxes a deemed return on your net assets on 1 January rather than your actual returns:
- In 2026 the box 3 rate is 36%, on a deemed return of 6.00% on investments and 1.28% on bank balances (provisional assessment, Belastingdienst).
- The tax-free allowance is €59,357 per person and €118,714 for fiscal partners.
- Box 1 rates go up to 49.50%.
How this compares with income from a side job depends on your income, your other assets and your actual return. Tax treatment depends on your circumstances and may change. Please consult a tax adviser.
See our guide to investing as an expat and our DEGIRO review for expats.
Dividends and savings interest
Shares and savings are part of your box 3 assets. Dutch dividend withholding tax is 15% (Belastingdienst) and can be relevant for credit against your tax; ask an adviser about foreign dividends.
Rental property
Whether rental income from property is taxed in box 1 or box 3 depends on the facts of your situation. If you own investment property, ask a tax adviser.
Setting Up as a ZZP
- Register with the KvK on kvk.nl; the fee is €85.15 (2026).
- Consider the KOR if your annual turnover will stay below EUR 20,000.
- Set up invoicing with numbered invoices for every payment. Dutch tools such as Moneybird are popular with ZZP; compare the options yourself.
- Consider a separate business bank account to keep records clear; bunq is one provider to compare.
- Keep records of every invoice and expense.
- File your income tax return including your profit.
Read our KvK registration guide and our guide to tax for freelancers and ZZP.
Common Mistakes to Avoid
- Not checking your employment contract for a secondary activities clause.
- Assuming side income is tax-free because of the 30% ruling. Check the conditions and ask an adviser.
- Mixing personal and business finances. Separate accounts make your records simpler.
- Not registering when you should. If you are genuinely running a business, register.
- Ignoring residence permit conditions. For non-EU expats, check before you start.
Related reading: KvK Registration Guide for Expats | Tax for Freelancers and ZZP in the Netherlands | Investing in the Netherlands as an Expat | 30% Ruling Eligibility Guide | DEGIRO Review for Expats | Dutch Employment Contract Explained | Best Accounting Software for Freelancers Netherlands | Dutch Business Bank Account for ZZP
External source: Belastingdienst: VAT info
Frequently Asked Questions
Can I do freelance work on the side while employed in the Netherlands?
Often yes, but check three things first. Your employment contract may contain a secondary activities clause (nevenwerkzaamheden) that requires you to notify your employer or ask permission. Your residence permit may limit the work you may do, so check its conditions and ask the IND if you are unsure. And if the work is regular and commercial, it may need KvK registration and must be declared on your tax return.
Do I need to register with the KvK for a side hustle in the Netherlands?
That depends on whether you run a business. The Belastingdienst looks at factors such as how regularly you work, whether you aim to make a profit and whether you act in a business-like way. Occasional small sales are different from offering services to customers regularly. The one-time KvK registration fee is EUR 85.15 in 2026 (KVK). When in doubt, ask the KvK or the Belastingdienst.
How is side hustle income taxed in the Netherlands?
Profit from a business or from other activities (overige werkzaamheden) is taxed in box 1 together with your other income. In 2026 the box 1 rates for people below AOW age are 35.75% up to EUR 38,883, 37.56% up to EUR 78,426 and 49.50% above that (Belastingdienst). Entrepreneurs who meet the hours criterion (at least 1,225 hours a year, and more time on the business than on other work, with an exception) can use the zelfstandigenaftrek (EUR 1,200 in 2026) and the mkb-winstvrijstelling (12.7% in 2026).
How does a side hustle affect my 30% ruling?
The 30% ruling relates to the salary from your employer. Check the Belastingdienst's conditions to see how other income is treated, and consult a tax adviser. In any case the profit from a side hustle is declared in your tax return.
What is the difference between box 1 and box 3 for passive income?
Box 1 taxes income from work and home ownership. Box 3 taxes a deemed return on your savings and investments rather than your actual returns. For the 2026 provisional assessment the Belastingdienst uses a deemed return of 1.28% on bank balances and 6.00% on investments and other assets, and the box 3 rate is 36%. The tax-free allowance is EUR 59,357 per person (EUR 118,714 for fiscal partners). Which route is cheaper depends on your situation.
Can I rent out a room in my Dutch home for income?
If you rent a room in your own home for a longer period and meet all the conditions, the kamerverhuurvrijstelling applies: total rental income up to EUR 6,633 in 2026 (including payments for energy and use of appliances) does not have to be declared. Conditions include that the room is not an independent dwelling and that you and the tenant are registered at the same address. Short-term rental, for example through Airbnb, is not covered (Belastingdienst). Check your rental contract or mortgage terms before you sublet.