Self Assessment tax calculator, 2026/27
Enter your income for the tax year and see the estimated income tax, National Insurance and payments on account due on 31 January.
The self assessment tax calculator runs on the rates and thresholds HMRC has published for the 2026/27 tax year, so the figures you see reflect the position your company is actually filing on rather than a historic set of bands. Change any input and the result recalculates immediately, with no sign-up and nothing sent anywhere.
If you are a director of a UK limited company, use it as a first look before a decision rather than as the decision itself. 2026/27 rates for England, Wales and Northern Ireland. Scottish taxpayers have different income tax bands. Real company positions bring in other income, reliefs, group structures and prior year adjustments that a single page of inputs cannot see, which is why the workings are written out below under personal & self assessment tax. Read those, then check the numbers against your own accounts, and speak to us if anything looks materially different from what you expected.
Last reviewed 12 September 2026 for the 2026/27 tax year. Reviewed by Waqas Sagar, Member of ICAEW, Fellow of ACCA, Fellow of AAT.
Regulated by
Regulated & AML supervisor
AAT fellow member
Xero Gold PartnerCertified advisor
QuickBooks PartnerCertified ProAdvisor100+ yearsCombined team experienceFully insuredUp to £2m indemnitySelf Assessment tax calculator
Result, 2026/27
Estimated tax and NI due
Income tax
Class 4 National Insurance
6% between £12,570 and £50,270, 2% above.Payment on account (each)
Due 31 January and 31 July towards next year's bill.Filing deadline
Paper returns are due by 31 October.Illustration only, figures are based on the rates you have selected and the information entered. Please check your own position with us before acting.
Estimates for the 2026/27 tax year using published GOV.UK rates. Switch between 2026/27 and 2025/26 above.
Who needs to file
Company directors with untaxed income, the self-employed with turnover over £1,000, landlords, people with significant dividend or savings income, and anyone caught by the high income child benefit charge generally need to file a return.
Registering for Self Assessment for the first time has its own deadline: 5 October following the end of the tax year in which the income arose.
Payments on account catch people out
If your balancing payment exceeds £1,000, HMRC also asks for two payments on account towards the following year, each half of the current bill, due 31 January and 31 July. Your first January after a profitable year can therefore ask for 150% of the tax you expected.
Making Tax Digital for Income Tax
MTD for Income Tax begins in April 2026 for sole traders and landlords with qualifying income above £50,000, with £30,000 following in April 2027. Quarterly updates from digital records replace the once-a-year scramble, so it is worth getting bookkeeping in order before then.
What this means for your company
Treat the result as a planning figure for the 2026/27 tax year. If it changes what you were about to do, take a director's salary, a dividend, a large asset purchase or a filing decision, check it against your own accounts first. We can review the position with you and confirm the tax treatment before you commit.
Frequently asked questions
When is the Self Assessment deadline?
31 January after the end of the tax year for online returns and payment. Paper returns are due by 31 October.
What is the penalty for filing late?
£100 immediately, then daily penalties of £10 a day after three months up to £900, further penalties at six and twelve months, plus interest on unpaid tax.
Do directors always need to file a return?
Not automatically, but most do, because dividends and other untaxed income need reporting. HMRC will also expect a return if it has issued a notice to file.
What are payments on account?
Advance instalments towards next year's bill, each half of the current year's liability, due on 31 January and 31 July. They apply if you owe more than £1,000 and less than 80% of your tax was collected at source.
Keep going
Related calculators
Same rates, different question.
Dividend tax calculator
Calculate the personal tax on dividends from your limited company for 2026/27, using the £500 dividend allowance and the 10.75%, 35.75% and 39.35% rates.
CalculatorSalary vs dividend calculator
Compare how much of your company profit reaches you as salary versus dividends in 2026/27, including corporation tax, employer NI, employee NI and dividend tax.
CalculatorLate filing penalty calculator
Work out Companies House late filing penalties and HMRC corporation tax penalties for a limited company, by how late the accounts and return are.