UK Self Assessment Tax Estimator (2025-26)

Estimate your 2025-26 Self Assessment bill

If you are self-employed or a landlord, your 2025-26 tax return and any tax you owe are due by 31 January 2027. Enter your income and expenses above to see an estimated bill: Income Tax by band, Class 4 National Insurance, the balancing payment, and the two payments on account for next year.

The 2025-26 rates used

Personal Allowance:  £12,570 (tapers by £1 per £2 of income over £100,000, zero at £125,140)
Income Tax:          20% up to £50,270  ·  40% up to £125,140  ·  45% above
Class 4 NI:          6% on profits £12,570–£50,270  ·  2% above £50,270
Class 2 NI:          not payable since April 2024

Class 4 National Insurance is charged on self-employment profit only. Other income — a salary, a pension, rent — counts towards Income Tax but not towards Class 4.

Worked example

A sole trader with £60,000 of self-employment profit and no other income:

Total income            £60,000
Personal Allowance      £12,570
Taxable income          £47,430

Income Tax  20% × £37,700    £7,540.00
            40% ×  £9,730    £3,892.00
Income Tax total                £11,432.00
Class 4 NI   6% × £37,700    £2,262.00
             2% ×  £9,730      £194.60
Class 4 total                    £2,456.60
Total 2025-26 bill              £13,888.60

Balancing payment, 31 Jan 2027  £13,888.60
First payment on account, 31 Jan 2027   £6,944.30
Second payment on account, 31 Jul 2027  £6,944.30
Total due by 31 January 2027    £20,832.90

The January total is bigger than the bill itself: the balancing payment and the first payment on account fall on the same day.

Payment dates

• 31 January 2027 — online return deadline, balancing payment, and the first payment on account for 2026-27.
• 31 July 2027 — second payment on account for 2026-27.

Payments on account only apply when your Self Assessment bill is £1,000 or more. If more than 80% of your tax was collected at source, for example through PAYE, you do not make them either.

What this estimate does not cover

Pension contributions and Gift Aid change your basic rate limit; Marriage Allowance transfers part of a partner’s Personal Allowance; student loan repayments are charged separately; capital gains have their own rates and allowance. None of those are in this estimate. Scotland also has different income tax bands, so if you are a Scottish taxpayer this page’s figures do not apply. Check the final numbers against your HMRC online account before you pay.