Zzp naast loondienst

A side business, without a second job in admin.

A few clients next to your salary, a few hours on the weekend. The work is the fun part; the invoices, the btw and the tax letter are not. Bilio keeps a small side business tidy in minutes a month, free, in English.

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The short answer

How is a side business taxed in the Netherlands?

Your side income is added to your salary and taxed in your income tax return, usually at your highest rate. If the Belastingdienst sees you as an entrepreneur, it is profit from business and you get the MKB-winstvrijstelling; next to a full-time job you rarely meet the 1,225-hour criterion, so the zelfstandigenaftrek usually doesn’t apply. Otherwise it is income from other work. For btw, most side businesses can join the KOR and charge no btw if turnover stays under €20,000.

Checked by Stefka Ivanova, founder of Bilio and a freelancer in Amsterdam, on .

Register at the KVK
Yes, if you work for clients regularly
KOR (no btw)
Possible under €20,000 turnover a year
Hours criterion
1,225 hours: rare next to a full-time job
SME profit exemption
12.7%, if you count as an entrepreneur
Tax on side income
Added to your salary in the yearly return
How Bilio helps

What changes when Bilio does the admin.

You have a salary and a side business: a few clients, evenings and weekends.

  • 01

    Invoices in two minutes

    A client, a line, a price. Bilio adds your KvK and btw numbers, the date, the next invoice number and the right btw, or none if you joined the KOR. Send it from Bilio and see when it’s opened.

  • 02

    KOR handled for you

    Joined the small business scheme? Bilio leaves btw off your invoices, prints the KOR line, and shows your turnover for the year against the €20,000 limit.

  • 03

    Know what to put aside

    Bilio shows profit so far this year. Ask the AI advisor how much to set aside for tax, since side income is taxed on top of your salary.

  • 04

    Expenses that count

    A laptop, software, a course. Snap the receipt, mark it deductible, and it lands in the right cost group for your income tax return.

  • 05

    Hours, if you bill by the hour

    Start a timer for each evening’s work, or type the hours afterwards; Bilio turns them into the invoice. Free, like the rest of what a small side business needs.

  • 06

    Free while it’s small

    Unlimited invoices, hours and clients on the free plan, forever. Upgrade only if the side business grows.

Natively AI

Ask about your own numbers, in plain English.

Bilio’s AI financial advisor answers from your invoices and expenses (Pro). Or connect Claude, ChatGPT or Cursor to Bilio and ask there (Pro and Business); nothing is sent or changed without your OK.

AI does

Read receipts, suggest categories, add up the quarter, explain the btw boxes and the income tax lines, draft invoices.

You do

Check the figures and file them. Bilio doesn’t file for you and doesn’t give tax advice; for a complex situation, see an adviser.

Connect your assistant
  1. How much have I earned from my side business this year?
  2. How much should I set aside for tax on that?
  3. How close am I to the €20,000 KOR limit?
  4. Draft an invoice for last weekend’s shoot: €450.
  5. Who still hasn’t paid me?
The Dutch tax year

Four btw returns and one income tax return.

The btw return is due by the last day of the month after each quarter; the income tax return by 1 May the year after. In the KOR you file no btw returns at all; you only file the income tax return. Not in the KOR? Then the quarterly btw return applies too, even in a quarter with no invoices.

  • €1,200zelfstandigenaftrek 2026, with 1,225 hours
  • €2,123startersaftrek, up to 3 times in your first 5 years
  • 12.7%MKB-winstvrijstelling on profit after deductions
  • €20,000turnover limit for the KOR

Figures for 2026 from the Belastingdienst and business.gov.nl. Check them before you file.

Dutch tax terms

The tax office’s Dutch, in plain English.

KOR (kleineondernemersregeling)
The small business scheme. With turnover under €20,000 a year you can choose to be exempt from btw: you charge no btw and file no btw returns, but you cannot reclaim btw on costs.
Urencriterium
The hours criterion: at least 1,225 hours a year on your business, and more than half your working time (that second test does not apply in your first five years). Admin and finding clients count.
Zelfstandigenaftrek
The self-employed deduction: €1,200 off your profit in 2026, if you meet the hours criterion (urencriterium).
MKB-winstvrijstelling
The SME profit exemption: 12.7% of your profit after the self-employed deductions is tax-free in 2026. No hours criterion needed.
Resultaat uit overige werkzaamheden
Income from other work: freelance income when the Belastingdienst does not see you as an entrepreneur. Taxed in your income tax return, costs deductible, but no entrepreneur deductions.
KVK
The Dutch Chamber of Commerce (Kamer van Koophandel), where you register your business. You get a KvK number to put on every invoice, and the Belastingdienst sends your btw number.
Questions

Common questions.

Can I be a zzp’er next to my job?
Yes. Check your employment contract for a side-job clause, register at the KVK if you work for clients regularly, and declare the income in your tax return. Doing paid work without declaring it is illegal.
Do I have to register at the KVK for a side business?
If you work for clients regularly and aim to make a profit, yes. A one-off job or a hobby that earns a little usually does not need registration, but the income is still taxed as income from other work.
Should I join the KOR?
If your clients are mostly consumers and turnover stays under €20,000 a year, the KOR often saves money: you charge no btw and file no btw returns. If your clients are businesses, or you buy expensive equipment, staying out lets you reclaim btw. Our KOR guide (in Dutch) walks through it.
Do I get the zelfstandigenaftrek next to a job?
Only if you spend at least 1,225 hours a year on your business, which is rare next to a full-time job. The MKB-winstvrijstelling does apply if you count as an entrepreneur for income tax.
Does Bilio file my taxes?
Bilio prepares the figures; you file them yourself in Mijn Belastingdienst Zakelijk (btw) and in your income tax return. Bilio does not file for you and does not give tax advice.

Guides

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Get started

Your first invoice takes four minutes.

Create an account with your email and follow the five-step setup: business details, VAT and KvK, IBAN, first client, first invoice. No card, no setup fee, no downloads. Cancel any time and take your data with you.

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