Self Assessment deadline: what to send us by 31 January
Who this applies to
If you file a Self Assessment tax return, the main filing and payment deadline is 31 January each year. That covers the tax year that ended the previous 5 April — so the January 2027 deadline relates to the year to 5 April 2026.
What to send us
Send these as soon as you can — ideally before mid-January so we are not working to the last minute:
- Your UTR (Unique Taxpayer Reference), if we do not already have it on file
- P60 from employment, if you had a job in the year
- P11D or benefits summary, if your employer provided a company car, medical insurance, or other benefits
- Bank statements or a summary for any rental property
- Dividend vouchers and interest certificates
- Capital gains paperwork if you sold shares, a second property, or other chargeable assets
- Details of any side income — freelancing, consultancy, online sales, and so on
- A note of payments on account already made, if you know them
If something does not apply to you, say so — a quick “not relevant this year” saves us chasing the wrong documents.
Common things people forget
- Child Benefit — high earners may need to pay the High Income Child Benefit Charge even if they did not receive the payments directly
- Pension contributions — tell us about personal payments, not just workplace schemes
- Working from home — only claim what you can support; round numbers with no basis are easy to challenge
- Joint rental accounts — we need your share of income and expenses, not just the total on the mortgage statement
What happens if we miss the deadline
Late filing and late payment both attract penalties and interest. If you know you will be late, tell us early — we can sometimes reduce exposure, but we cannot undo a missed deadline after the fact.
What we will do once we have your records
We prepare the return, explain anything that looks unusual before submission, and confirm what you owe (or what HMRC owes you). If payments on account are due, we will flag those dates too.