Self Assessment Tax Calculator — 2025/26 & 2026/27
Your exact tax bill. Income tax, NI, expenses, payments on account — everything you need before filing with HMRC.
100% Free Calculation
Full tax calculation with band breakdown. No signup needed. Only pay if you want the PDF report.
HMRC 2025/26 & 2026/27 Rates
All tax bands, NI thresholds, and allowances verified against current HMRC published rates.
Your Data Stays Private
All calculations run in your browser. No data sent to any server until you choose to pay.
Built for people who hate tax forms.
Whether you're freelancing, renting out property, or driving for Uber.
Freelancers
Claim every expense you're entitled to. Know exactly how much to save each month.
Landlords
Calculate rental profit correctly after mortgage interest, repairs, and insurance.
Side Hustlers
Uber, Etsy, Deliveroo — find out if you need to file and what you can claim.
Ready to find out what you owe?
Takes under 15 minutes. No signup. No credit card. Just answers.
Free to use · Pay only for the PDF report (£12.99)
Do you need to file a Self Assessment?
You need to file a 2025/26 return if any of the following apply:
- You were self-employed with income over £1,000.
- You earned over £100,000 from employment.
- You received untaxed income — e.g. rental income, or dividends above £500.
- HMRC has asked you to send a return.
Not sure? The calculator above includes a “Do I need to file?” check.
Self Assessment Calculator
2025/26 & 2026/27
Your exact tax bill. Income tax, NI, expenses, payments on account — everything you need before filing with HMRC.
UK income tax rates. Simplified.
Personal allowance is £12,570 — reduced by £1 for every £2 earned over £100,000. Scotland has separate bands from 19% to 48%.
Basic Rate
20%
£12,571 – £50,270
Higher Rate
40%
£50,271 – £125,140
Additional Rate
45%
Over £125,140
How do payments on account work?
If your Self Assessment bill is more than £1,000 and less than 80% of your tax was collected at source (for example through PAYE), HMRC asks you to make payments on account — advance instalments toward next year’s bill. Each instalment is 50% of your current bill. The first is due on 31 Januaryalongside your balancing payment, and the second on 31 July. This catches many first-time filers out, so our calculator flags it in your results.
Worked example · £4,000 tax bill
- 2025/26 balancing payment£4,000
- First payment on account (50%)£2,000
- Second payment on account (50%)£2,000
- Due 31 January 2027£6,000
- Due 31 July 2027£2,000
Built & maintained by Omkar Sarswat · figures reviewed against HMRC guidance, April 2026.
Questions and answers.
What is UK Self Assessment?+
Self Assessment is the system HMRC uses to collect Income Tax from people who need to report income that hasn't been taxed at source. This includes self-employed individuals, landlords, people with dividend or savings income above their allowance, and anyone earning over £100,000.
When is the Self Assessment deadline for 2025/26 and 2026/27?+
The online filing deadline for the 2025/26 tax year is 31 January 2027 (paper returns by 31 October 2026). For the 2026/27 tax year, the online deadline is 31 January 2028. Late filing attracts an automatic £100 penalty, increasing to £10/day after 3 months late.
Do I need to file a Self Assessment tax return?+
You need to file if you were self-employed with income over £1,000, earned over £100,000 from employment, received untaxed income (e.g. rental, dividends above £500), or HMRC has asked you to file. If in doubt, use HMRC's online tool to check.
What happens if I miss the Self Assessment deadline?+
An automatic £100 penalty applies if you file even one day late. After 3 months, HMRC adds £10/day (up to £900). After 6 months, an additional 5% of tax owed (or £300, whichever is higher). After 12 months, another 5% or £300.
How do payments on account work?+
If your tax bill exceeds £1,000 (after PAYE deductions), HMRC requires advance payments toward next year's bill. Each payment is 50% of your previous year's bill. The first is due 31 January, the second 31 July.