Who may need to file
Use HMRC's checker for your circumstances. Not every untaxed amount automatically requires a return.
- Sole traders with gross trading income over £1,000 and partners in a business partnership
- Landlords: contact HMRC above £1,000 rental income; a return is normally required above £2,500 after expenses or £10,000 before expenses
- People with reportable untaxed dividends, overseas income or capital gains
- People claiming relief through a return; some pension relief can instead be claimed directly from HMRC
- Anyone HMRC has asked to file
2026/27 deadlines
The full Self Assessment timeline, from registration to payment
| Date | What's due |
|---|---|
| 5 October 2027 | Register if filing for the first time |
| 31 October 2027 | Paper return |
| 31 January 2028 | Online return and balancing payment |
| 31 July 2028 | Second payment on account |
Penalties
A late return costs £100 straight away, even if you owe nothing, with more after three, six and twelve months. Late payment adds interest and further penalties.
Estimate your tax return bill
Enter your income, business or property expenses and any pension or Gift Aid reliefs to see the Income Tax and Class 4 NI due, and what's left to pay after PAYE.
Use the Self Assessment Calculator to see what you would save
Filling in your return
Ready to file? Our step-by-step guide covers registering, logging in, each section of the online return and paying the bill.
A return and a payment are different tasks
Keep filing records alongside a separate payment plan. Estimating the year's liability does not by itself confirm that a return has been submitted or identify every amount due on a payment date.
Try it with your own numbers
Estimate your Self Assessment tax return bill for 2026/27.
Frequently asked questions
Do I still file if my salary is over £150,000?
From 2024/25, PAYE income alone does not require a return solely because of its amount. You may still need to file for other reasons or if HMRC asks you to.
Check it on GOV.UK: Income Tax rates and allowances (opens GOV.UK in a new tab) · Self-employed National Insurance rates (opens GOV.UK in a new tab)
Sources
Tax year 2026/27. Check these official sources for current rules and deadlines.
Related calculators
- Self Assessment Calculator — Estimate your Self Assessment tax return bill for 2026/27.
Related guides
- The Self Assessment Timeline: From Registration to Payment — The Self Assessment timeline in order: register by 5 October, wait for your UTR and activation code, file by 31 October or 31 January, pay by 31 January, and what late filing costs.
- How to Complete a Self Assessment Tax Return — A step-by-step guide to filling in your Self Assessment tax return online: registering, your UTR, what to have ready, each section, submitting and paying by 31 January.
- UK Tax Year Planner 2026/27: Deadlines, Tax Codes and Allowances — Every key date in the 2026/27 UK tax year: Self Assessment deadlines, payments on account, when tax codes change, and when to use or claim your allowances.
- Tax for the Self-Employed — How sole traders are taxed in the UK: Income Tax on profit, Class 4 NI, allowable expenses and payments on account.
- Capital Gains Tax Explained — How Capital Gains Tax works in 2026/27, the £3,000 allowance, 18% and 24% rates, and when you need to report.
- Dividend Tax Explained — How dividends are taxed in 2026/27 after the rates rose to 10.