UK Self-Assessment Tax Calculator 2026/27 (Self-Employed)
Estimate your Self Assessment bill for 2026/27 — income tax and Class 4 National Insurance on self-employed profits, plus other income — with payments on account and the January/July deadlines.
Estimates only — not tax advice. Tax rules change and depend on your situation; check with the tax authority or a tax professional.
How to use
- 1Enter your self-employed profit (income minus allowable expenses).
- 2Add employment income and tax already paid through PAYE.
- 3See the bill, payments on account and due dates.
How it's calculated
Income tax on all income − tax already deducted + Class 4 NI (6% on profits £12,570–£50,270, 2% above). Payments on account = 50% each of this year's bill, due 31 January and 31 July, unless the bill is under £1,000 or 80%+ was taxed at source.
Frequently asked questions
When is the 2026/27 tax due?
The return and balancing payment are due by 31 January 2028. Payments on account for 2027/28 are due 31 January 2028 and 31 July 2028.
Do I still pay Class 2 NI?
No — Class 2 is no longer charged. You can pay it voluntarily to protect your State Pension record if your profits are under £6,845.
What is Making Tax Digital?
From April 2026, sole traders and landlords with qualifying income over £50,000 must keep digital records and send quarterly updates to HMRC.