How the estimate is calculated
Freelens does not apply a flat percentage to what your clients pay you. It works out income tax and the Zvw contribution the way the Belastingdienst does, in this order.real brackets, with the deductions and tax credits you qualify for.
Tax year 2026, for someone who has not reached AOW age.Config nl-2026.1, every figure checked against belastingdienst.nl on 2026-08-03.
The order it works in
- Start with profit: revenue excluding VAT, minus business costs.
- Subtract the zelfstandigenaftrek and, if you qualify, the startersaftrek.
- Subtract the MKB-winstvrijstelling from what is left.
- Apply the income tax brackets to that figure.
- Subtract the algemene heffingskorting and the arbeidskorting, which come off the tax owed rather than off your income.
- Add the Zvw contribution, which is a separate bill with its own rate and its own ceiling.
Income tax brackets
| Taxable income | Rate |
|---|---|
| € 0 to € 38.883 | 35.75% |
| € 38.883 to € 78.426 | 37.56% |
| Above € 78.426 | 49.5% |
The first bracket includes premies volksverzekeringen, which are only levied on income up to that ceiling.
Deductions and credits
- Zelfstandigenaftrek € 1.200, if you spend at least 1.225 hours a year on the business.
- Startersaftrek € 2.123, on top, for up to three of your first five years.
- MKB-winstvrijstelling 12.7% of what is left after those deductions.
- Algemene heffingskorting A credit subtracted from the tax you owe, not from your income. It is the full amount up to €29.736 and then tapers away, reaching zero at €78.427.
- Arbeidskorting A credit for people who work, including self-employed people. It is calculated on your arbeidsinkomen, which counts business profit BEFORE the entrepreneur deductions and the MKB-winstvrijstelling.
- Zvw contribution 4.85% on your profit after deductions, up to a maximum base of € 79.409.
- Tariefsaanpassing aftrekposten Above €78.426 your deductions would otherwise save you tax at 49,50%. A correction of 11,94% is added back so the benefit is capped at 37,56%.
A worked example
€ 40.000 profit, hours criterion met, no starter deduction, no other income. Every line below comes straight from the engine.
- Projected profit for the year
- € 40.000
- Zelfstandigenaftrek
- € 1.200
- Startersaftrek (not applied)
- € 0
- MKB-winstvrijstelling
- € 4.928
- Profit the tax is calculated on
- € 33.872
- Bracket 1 at 35.75%
- € 12.109
- Algemene heffingskorting
- € 2.850
- Arbeidskorting
- € 5.576
- Income tax after credits
- € 3.683
- Zvw contribution
- € 1.643
- Total to pay for the year
- € 5.326
- Already set aside
- € 0
- Still to set aside
- € 5.326
That is 13.3% of the profit overall, while the next euro earned is taxed at 39.1%. A payment already counted in the profit you expect carries its share of the whole year's bill, the first figure. Only income beyond that expectation is reserved at the second rate, because it lands on top of everything already counted.
What this estimate assumes
Nothing here is hidden to make the number look cleaner. These are the assumptions attached to every result the app produces.
- Calculated for tax year 2026 using config nl-2026.1, with every figure checked against the official source on 2026-08-03.
- This is a planning estimate, not tax advice and not an assessment. Your actual bill is set by the Belastingdienst on your annual return.
- Figures are for a taxpayer who has not reached AOW age, is taxed as an entrepreneur for income tax (ondernemer voor de inkomstenbelasting), and lives in the Netherlands.
- Income tax is assessed once a year on your total profit. This estimate projects the whole year, so it changes as your projected profit changes.
- Zvw is charged on your profit after the entrepreneur deductions and the MKB-winstvrijstelling. That is what the Zorgverzekeringswet (article 43) and the Wet inkomstenbelasting 2001 (article 3.2) prescribe.
- The algemene heffingskorting is calculated on your Box 1 income only. Box 2 and Box 3 income are not modelled and would reduce this credit, so anyone with such income will be under-reserved here.
- Employment income is counted so the bracket your freelance profit lands in is right. Tax your employer already withheld is only subtracted if you enter it.
- The Zvw maximum contribution base is applied to business profit alone. Article 43 of the Zorgverzekeringswet shares that maximum across a job and a business, so with employment income alongside the business this estimate can overstate Zvw at high combined income.
- Only the zelfstandigenaftrek, the startersaftrek and the MKB-winstvrijstelling are modelled. Investeringsaftrek, meewerkaftrek, stakingsaftrek, fiscale oudedagsreserve and loss carry-forward are not.
- Amounts to set aside are rounded up to the whole euro. Under-reserving produces a surprise bill; over-reserving only costs liquidity, and those two are not equally bad.
Where each figure came from
Only belastingdienst.nl. No aggregators, no comparison sites, no accountancy summaries. Each entry records the date it was checked.
bracketsChecked 2026-08-03Box 1 brackets 2026 for people who have not reached AOW age: 35,75% up to €38.883, 37,56% to €78.426, 49,50% above.
belastingdienst.nlbracketsChecked 2026-08-03Second, independent confirmation of the same three brackets and thresholds.
belastingdienst.nlbracketComposition.socialPremiumRateChecked 2026-08-03Premies volksverzekeringen 2026: AOW 17,90% + Anw 0,10% + Wlz 9,65% = 27,65%, levied on income up to €38.883, maximum €10.751.
belastingdienst.nlbracketComposition.incomeTaxRateChecked 2026-08-048,10%, published directly in the Wet IB 2001 art. 2.10 lid 1 tariefstabel, whose columns give 8,10% / 37,56% / 49,50% at the same €38.883 and €78.426 boundaries. Previously derived as 35,75% - 27,65%; the derivation matched the statute exactly. Documentation only; no calculation uses it.
belastingdienst.nldeductions.zelfstandigenaftrekChecked 2026-08-03€1.200 for 2026. Requires the urencriterium and not having reached AOW age at the start of the year. May not exceed profit before ondernemersaftrek unless startersaftrek applies. All three confirmed by Wet IB 2001 art. 3.76: lid 1 the urencriterium, lid 2 the €1.200 and the AOW condition, lid 5 the profit cap and its waiver for starters.
belastingdienst.nldeductions.zelfstandigenaftrek.conditionsChecked 2026-08-03Urencriterium is at least 1.225 hours a year. Unused zelfstandigenaftrek carries forward 9 years (not modelled).
belastingdienst.nldeductions.startersaftrekChecked 2026-08-03€2.123 for 2026, if you were not an entrepreneur in one or more of the five preceding calendar years and applied the zelfstandigenaftrek at most twice in that period. Wet IB 2001 art. 3.76 lid 3 states it as a verhoging OF the zelfstandigenaftrek ('wordt de zelfstandigenaftrek verhoogd met € 2123'), not a deduction in its own right, which is why it inherits that deduction's treatment under the tariefsaanpassing. Art. 3.76 lid 5 waives the profit cap for anyone entitled to this increase, which is what capWaivedBy encodes.
belastingdienst.nldeductions.mkb-winstvrijstellingChecked 2026-08-0312,7% of profit after it has been reduced by the ondernemersaftrek. Benefit calculated at a rate of 37,56%. Ordering confirmed by Wet IB 2001 art. 3.79a: the exemption is 12,7% of profit 'nadat dit bedrag is verminderd met de ondernemersaftrek'.
belastingdienst.nlrateAdjustmentChecked 2026-08-03Tariefsaanpassing 11,94% in 2026, applies above €78.426, capping deduction benefit at 37,56%. Wet IB 2001 art. 2.10 lid 2 gives the formula this engine implements: 11,94% of the amount by which income plus the deductions exceeds the top bracket boundary, capped at 11,94% of the deductions themselves. Art. 2.10 lid 3 onder a covers 'de ondernemersaftrek, bedoeld in artikel 3.74' as a whole rather than an itemised list, and art. 3.74 onder a puts the zelfstandigenaftrek inside it. Note lid 3 onder b admits the MKB-winstvrijstelling only where profit after the ondernemersaftrek is positive; see NEEDS_VERIFICATION.md item 8.
belastingdienst.nlcredits.algemene-heffingskorting.segmentsChecked 2026-08-03Not yet AOW age: €3.115 up to €29.736; then €3.115 - 6,398% x (verzamelinkomen - €29.736); €0 from €78.427. Wet IB 2001 art. 8.10 lid 2 states exactly this and names verzamelinkomen as the base, which is what NEEDS_VERIFICATION.md item 5 is about: the engine substitutes Box 1 income for it.
belastingdienst.nlcredits.arbeidskorting.segmentsChecked 2026-08-03Not yet AOW age: 8,324% to €11.965; €996 + 31,009% to €25.845; €5.300 + 1,950% to €45.592; €5.685 - 6,510% to €132.920; €0 from €132.921. Wet IB 2001 art. 8.11 lid 2 onder a-d states the same four rates and the same three thresholds, with the caps at €996, €5.300 and €5.685 and a floor at nil. The €2.840 seen on the Belastingdienst overview page appears nowhere in the Wet IB 2001; art. 8.11's closing sentence is a floor at the payroll-computed credit capped at €5.685, not a ceiling of €2.840. See NEEDS_VERIFICATION.md item 4.
belastingdienst.nlcredits.arbeidskorting.baseChecked 2026-08-03Arbeidsinkomen counts 'winst uit onderneming vóór ondernemersaftrek en mkb-winstvrijstelling', plus wages and resultaat uit overig werk. A different base from the algemene heffingskorting.
belastingdienst.nlsocialContributions.zvw.rateChecked 2026-08-03Bijdrage Zvw 4,85% for income not subject to employer withholding, including winst uit onderneming. Werkgeversheffing is 6,10% and does not apply here.
belastingdienst.nlsocialContributions.zvw.capChecked 2026-08-03Maximum bijdrage-inkomen 2026 is €79.409.
belastingdienst.nlsocialContributions.zvw.baseChecked 2026-08-04CONFIRMED. Zorgverzekeringswet art. 43 lid 2 onder b: the bijdrage-inkomen from a business is 'belastbare winst uit onderneming, bepaald volgens de regels van afdeling 3.2 van de Wet inkomstenbelasting 2001'. Wet IB 2001 art. 3.2 defines that as profit 'verminderd met de ondernemersaftrek en de MKB-winstvrijstelling'. So the base is profit after both, which is what profitAfterDeductions is. Sourced from the statute because no Belastingdienst page states the base; theirs say only 'winst uit onderneming'.
belastingdienst.nlsocialContributions.zvw.floorAtZeroChecked 2026-08-04Zorgverzekeringswet art. 43 lid 3: 'Het bijdrage-inkomen wordt ten minste op nihil gesteld' and is capped at the amount fixed by ministerial regulation. Confirms both the zero floor and the existence of the maximum applied here. Art. 43 lid 5 shares that maximum with wage income, which this engine does not model; see NEEDS_VERIFICATION.md item 7.
belastingdienst.nlbracketsChecked 2026-08-04Statutory cross-check of the whole Box 1 model against the Wet inkomstenbelasting 2001 as in force on 2026-01-01. Art. 2.10 lid 1 the bracket table and the 8,10% component; art. 2.10 lid 2 and 3 the tariefsaanpassing formula and what it covers; art. 3.2 belastbare winst; art. 3.74 the composition of the ondernemersaftrek; art. 3.76 the zelfstandigenaftrek, the starter increase and the profit cap; art. 3.79a the ordering of the MKB-winstvrijstelling; art. 8.10 and 8.11 the two credits. Every figure already taken from belastingdienst.nl matched. This entry is the single link for all of it, so the notes above can cite articles without repeating the URL.
belastingdienst.nlvatRatesChecked 2026-08-0321% standard, 9% reduced, 0% for cross-border supplies. No rate changed for 2026; logies moved from the 9% category to the 21% category on 1 January 2026, which is a classification change.
belastingdienst.nl
For what Freelens does and does not calculate more broadly, and when to talk to an accountant, see accuracy and sources.