Advance tax for ENK 2026
Advance tax for sole proprietorship: instalments and calculation
Learn how advance tax is calculated for your Norwegian sole proprietorship, when the four instalments are due, and how to adjust the tax if your income changes during the year.
The four tax instalments
First advance tax payment for the current tax year.
Second payment. You can request adjustment if your income changes significantly.
Third payment, often the largest if your income has grown during the year.
Final payment. Any remaining tax or refund is settled at the tax assessment the following year.
How advance tax works
- 1
Apply for advance tax
When you register your sole proprietorship, you submit form RF-1102 with expected business income. The Tax Administration calculates advance tax based on this.
- 2
Receive your advance tax notice
The Tax Administration sends you a notice showing how much to pay in each of the four instalments. The amount is normally split equally.
- 3
Pay each instalment
You pay by March 15, June 15, September 15 and December 15. Set up direct debit to avoid late payments.
- 4
Adjust during the year if needed
If your income changes significantly (up or down), you can apply to change the advance tax in Altinn. This avoids large unpaid balances or unnecessary payments.
- 5
Annual tax assessment
After the tax year, you file your tax return. If you have paid too much advance tax, you get a refund. If you have paid too little, you owe the difference.
Estimate your advance tax
Enter your expected annual profit (business income). The calculator estimates your advance tax using 2026 rates and splits it into four equal instalments.
Estimated advance tax for the year
0 kr
National insurance (trygdeavgift): 0 kr + income tax: 0 kr
Split into four instalments:
March 15
0 kr
June 15
0 kr
September 15
0 kr
December 15
0 kr
Estimate using 2026 rates. The Tax Administration sets the actual amount. If you also have salary income, use the tax calculator. Last verified against official sources: June 2026.
What does the result mean? At a profit of 0 kr, your estimated advance tax is 0 kr — about 0 kr per instalment.
How we calculate
Advance tax estimates the tax on your business profit for 2026: 10.8% national insurance (trygdeavgift) on business income plus income tax on the profit, paid in four equal instalments on 15 March, 15 June, 15 September and 15 December.
This is an estimate from a single profit figure. The Tax Administration sets your actual advance tax from the expected income you report, and you can adjust it during the year.
Worked example (650,000 kr expected business income, 2026 rates):
| Expected business income | 650,000 kr |
| Tax on general income (22%, after personal allowance) | 117,801 kr |
| Bracket tax (estimate) | 14,835 kr |
| Social security on personal income (10.8%) | 70,200 kr |
| Total advance tax for the year | 202,836 kr |
| Per instalment (divided by 4) | 50,709 kr |
What this calculator doesn't cover
- It estimates from one profit figure and assumes business income only — your actual advance tax is set by the Tax Administration from your reported expected income.
- It splits the year evenly; if you start partway through the year the instalments may differ.
- If your income changes, you can apply to adjust the advance tax during the year.
- Missing one instalment can make the remaining instalments fall due.
Next step
- Full tax calculation — estimate your full tax for the year
- Tax deductions — lower your taxable profit
- VAT — check if you must register for VAT
Common advance tax mistakes
- ✕Underestimating first-year income and paying too little advance tax — results in tax owed plus interest.
- ✕Missing an instalment and incurring late-payment interest.
- ✕Not adjusting advance tax when income grows significantly during the year.
- ✕Spending the money intended for tax — always set it aside in a separate account.
- ✕Not keeping ongoing accounts, leading to guesswork at tax return time.
Frequently asked questions about advance tax
When do I have to pay advance tax?+
Advance tax is paid in four instalments: March 15, June 15, September 15 and December 15. The amount for each instalment is stated in the notice you receive from the Tax Administration.
How is advance tax calculated?+
Advance tax is calculated based on expected business income and includes tax on general income (22%), bracket tax (trinnskatt), and social security contributions of 10.8% on calculated personal income (personinntekt). The Tax Administration does the calculation when you apply for advance tax.
What happens if I do not pay on time?+
You are charged late-payment interest from the due date. Additional reminder fees and debt collection may apply if non-payment continues.
Can I change the advance tax?+
Yes. If your income changes significantly (up or down), you can apply to change it in Altinn using the form for advance tax adjustment.
What is the difference between advance tax and remaining tax?+
Advance tax is what you pay in four instalments during the year. Remaining tax (restskatt) is what you owe after the annual tax assessment if advance tax did not cover the full tax claim.
Do I have to pay advance tax in the first year?+
Yes, as soon as the Tax Administration has calculated and issued advance tax for the business. If you start late in the year, the first instalments may have a shorter time between issuance and due date.
How much should I set aside for tax?+
A rule of thumb is to set aside 30–40% of profit in a separate tax account. The exact percentage depends on income level and whether you have other salary income.
What is the social security contribution for self-employed?+
The social security contribution on personal income from business (personinntekt) is 10.8% in 2026 (reduced from 10.9% in 2025). This is higher than for regular salary income (7.6%) because self-employed individuals do not have an employer paying employer social security on top.
Official sources
- Skatteetaten (English) ↗
The Norwegian Tax Administration in English with information on advance tax for sole proprietorships.
- Altinn (English) ↗
Official government portal with guides on advance tax instalments and how to pay or adjust them.
Related calculators and guides
Explore other tools for Norwegian sole proprietorships.