Freelancing alongside a salaried job

You have a full-time job. It pays the bills, offers stability, and you're not leaving it tomorrow. But you also want to freelance — maybe a side project, consulting work, or a growing business you're building on evenings and weekends. Can you do both? Yes. Will it be more complex? Absolutely. Should you understand the traps before you start? Definitely.

The Dutch tax system doesn't forbid combining employment and freelancing, but it does set some rules that trip up the unwary.

The urencriterium challenge#

Here's the first hard truth: the 1,225-hour urencriterium counts all your working hours, in both your job and your freelance business.

If you work 40 hours/week in a job (2,000 hours/year) plus a 10-hour/week side hustle (500 hours/year), you've hit 2,500 hours total — no problem.

But if you work 40 hours/week in a job plus a 5-hour/week freelance gig (260 hours/year), you have only 2,260 hours total — still way above 1,225.

The real squeeze comes for people in part-time employment or those with significant unpaid time. A 30-hour/week job (1,560 hours) plus a 10-hour/week freelance side (520 hours) = 2,080 hours, still fine.

But a 20-hour/week job (1,040 hours) plus a 10-hour/week side gig (520 hours) = 1,560 hours — still above the threshold, actually.

The actual risk: you work part-time and take on very little freelance work. A 20-hour/week job (1,040 hours) plus a 2-hour/week side gig (104 hours) = only 1,144 hours, below the 1,225 threshold. You'd lose the zelfstandigenaftrek and startersaftrek.

The lesson: if you're combining employment and freelancing, track both carefully so you can prove you hit 1,225 hours if challenged.

• Log hours in your job (use payroll or a time-tracking app)
• Log hours in your freelance work (invoices and time sheets)
• Keep clear separation between the two on your record
• Add them up quarterly to monitor progress toward 1,225 hours

How both incomes are taxed#

Here's the good news: your job income and freelance income are both taxed under the same box 1 (employment and self-employment income). They add together, and you pay one progressive tax on the combined total.

Example:

• Salaried job: €45,000/year
• Freelance net profit: €12,000/year
• Combined taxable income: €57,000 (before deductions)

The two forms of income don't get separate tax treatment — they're combined, and you pay the same marginal rate on both. This is actually good for you if your freelance profit is small (it doesn't push you into a higher bracket) and neutral if it's significant.

The tricky part: the Belastingdienst wants you to file both an employment tax form (Inkomstenbelasting over wages) and a self-employment return (Inkomstenbelasting over business profit). But they net together in the end.

The heffingskorting (general tax credit) problem#

Here's a common pitfall: the heffingskorting (general tax credit / algemene heffingskorting) — a credit that reduces your final tax bill — is usually already applied by your employer to your wage.

Your employer's system withholds a certain amount from your salary every month, accounting for the heffingskorting. When you file your freelance business, the Belastingdienst will see you've already claimed the credit on your employment income.

You cannot claim it twice.

If your freelance profit is very small and your employment income is large, this is a non-issue. But if your freelance income is substantial, you might end up with a tax bill at the end of the year because the credit was fully used by your employment withholding.

How to avoid it:

• Talk to your employer's payroll about reducing your wage withholding if you have significant freelance income. They can adjust the tax-withholding code to account for your self-employment.
• Or, file your tax return and accept that you might owe extra.
• Or, request a voorlopige aanslag (provisional assessment) that accounts for both income sources, so you pay monthly instalments that reflect your true tax across both.

Should you use the KOR?#

The KOR (small business scheme) allows you to be exempt from charging VAT if your turnover is below €20,000/year. This is often a smart move for freelancers with side income.

Pros of KOR:

• You don't charge VAT on your freelance invoices (simpler, lower price for clients, easier for B2C)
• You don't deduct VAT on your costs (you don't file BTW returns, saving admin time)
• Especially good if your clients are private individuals, not businesses

Cons of KOR:

• You can't reclaim VAT on your business purchases (travel, software, equipment)
• Loses appeal if you have significant business expenses
• Less attractive if your clients are companies expecting VAT invoices

For a small side hustle, KOR is often the right call. For a growing freelance business, regular VAT registration may make more sense.

Since 2025, the KOR rules relaxed — you can opt in and out more flexibly year to year, rather than being locked in for three years.

The cash-flow reality#

Combining a salary and freelance income creates uneven cash flow. Your salary arrives on schedule every month. Your freelance invoices might arrive irregularly, and you may wait 30–60 days to be paid.

Practical tips:

• Keep a separate business account for freelance income and costs. Makes it far easier to track which money is which.
• Reserve a buffer. Your salary covers living costs; let your freelance income build a reserve for taxes and irregular expenses.
• Invoice quickly after delivering freelance work. The sooner you bill, the sooner you get paid.
• Track time religiously. If you're questioned on the urencriterium, you need proof you hit the hours.

The conflict-of-interest question#

Before you start, check your employment contract and your employer's rules. Some employers forbid outside work without permission. Some require you to disclose side income. Some have non-compete clauses.

If your freelance work competes with your employer's business, or uses time/resources your employer expects, you could face pushback or even termination.

Best practice:

• Read your contract carefully
• If in doubt, ask your employer or HR
• Keep your side gig truly separate — don't use company resources, don't work during company time, don't involve company clients

Most employers are fine with a non-competing side hustle, but assuming without asking is how people get fired.

Frequently asked questions#

Combining a job and freelance work is entirely legal and increasingly common. The keys are: (1) hit the urencriterium to get your deductions, (2) understand that both incomes are taxed together, (3) manage the heffingskorting carefully, (4) choose the KOR wisely, and (5) keep crystal-clear records of both income streams. Use ZZP Belasting to track your freelance hours and profit alongside your employment income, so you're always audit-ready.

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