How to file your income tax return in United Kingdom

Who must file

In most countries, anyone with income above the tax-free amount who was not fully taxed through payroll withholding must file: the self-employed, landlords, company directors and anyone with more than one income source. Companies file their own return. Check HM Revenue and Customs (HMRC)'s rules for employees, who are sometimes exempt or auto-assessed.

Self-employed people with turnover over £1,000, landlords, higher earners with untaxed income, and anyone HMRC sends a notice to file. Most employees on PAYE alone do not file.

Tax year and deadline

Every country fixes a tax year and a filing deadline a few months after it ends. HM Revenue and Customs (HMRC) publishes both. Put the deadline in your calendar with a reminder a month before, because late filing is penalised even when no tax is due.

Tax year: 6 April to 5 April.

Tax year 6 April to 5 April. Paper returns by 31 October; online returns and the balancing payment by 31 January; payments on account on 31 January and 31 July.

What you need

Your VAT number and login for HM Revenue and Customs (HMRC)'s online service.
Employment income statements from each employer showing pay and tax withheld.
Your invoices, bank statements and expense records if you are self-employed.
Certificates for pension contributions, insurance, donations and other reliefs you will claim.
Last year's return, to check nothing is missed.

Filing step by step

Sign in to your HMRC account with your Government Gateway ID and UTR.
Work through the employment, self-employment and other income pages using your P60, P11D, invoices and bank records.
Claim allowable expenses and pension or Gift Aid relief.
Submit, note the calculation, and pay by 31 January.

Employees and salary tax

Employers in United Kingdom withhold income tax from salaries under the 2025/26 (England, Wales, NI) bands and pay it to HM Revenue and Customs (HMRC). The United Kingdom salary tax calculator shows the tax and take-home for any gross salary, which is a quick way to check your payslip before you file.

If you are late

Late returns attract a fixed penalty and late payment attracts interest, both set by HM Revenue and Customs (HMRC). File even if you cannot pay in full; penalties for not filing are usually heavier than for paying late, and most authorities allow instalment plans.

Questions people ask

Do I need to file if my employer already deducted tax?

It depends on United Kingdom's rules. Some countries require every taxpayer to file, some auto-assess employees, others exempt employees with a single employer and no other income. The rule for United Kingdom is set out above.

What if I had no income?

If you are registered with HM Revenue and Customs (HMRC), you may still have to file a nil return. Failing to do so is treated as a late return in many countries.

Can I file late without a penalty?

Rarely. Some authorities allow an extension if requested before the deadline. Otherwise file as soon as possible; penalties often grow with time.

Should I use an accountant?

If you are employed with no other income, the online service is designed for you. If you run a business or have foreign income or property, an accountant usually saves more than the fee.

Sources

How this guide was made

Written from published tax-authority guidance and reviewed on 2026-09-03. Everything here is indicative rather than a ruling on your circumstances, and rules change. Confirm anything you rely on with HM Revenue and Customs (HMRC) before acting on it, and tell us if you find something out of date so we can correct it.