Self Assessment Deadline 2027: Penalties and Dates Explained (UK), by MAS Ltd on YouTube. 6 min 55 s.
- Video length
- 6 min 55 s
- Time to do it
- 20 minutes
- Difficulty
- Easy
- Steps
- 8
What you need
Steps
Work out whether you need a return. You usually do if you were self-employed and earned over £1,000, or you had untaxed income such as rent, dividends or savings interest.
If this is your first return, register for Self Assessment on gov.uk. Allow several weeks for your Unique Taxpayer Reference to arrive by post before the deadline.
Note the dates for the 2025/26 tax year: 31 October 2026 for a paper return, and 31 January 2027 for an online return and for paying what you owe.
Collect your records before you start: income, expenses, P60s, bank interest, pension contributions and any other untaxed income.
Sign in to your HMRC account and fill in the online return. Check each figure against your records, then submit it well before 31 January 2027.
Pay your bill by 31 January 2027. If you cannot pay in full, set up a Time to Pay plan with HMRC before the deadline, not after.
If you miss the deadline, file straight away. The £100 penalty is fixed, then £10 a day builds up to £900, with 5% of the tax or £300 added at 6 and 12 months.
If something outside your control stopped you filing, appeal the penalty online and send evidence such as medical letters or bereavement documents.
Tips and common mistakes
The £100 late filing penalty applies even when you owe HMRC nothing.
Filing on time stops the daily penalties, even if you still need a payment plan for the tax itself.
There is a second payment on account due on 31 July, so budget for both dates.
Check gov.uk for current rates and dates, as penalties and deadlines can change.
Questions
How much is the first late filing penalty?
It is £100, charged the day after the deadline. Daily penalties of £10 then start three months later and run up to £900.
Can I pay my tax bill in instalments?
Yes. Contact HMRC before 31 January to arrange a Time to Pay plan. Interest still runs on the unpaid amount.
What counts as a reasonable excuse for a late return?
Something unexpected and outside your control, such as serious illness, a bereavement or lost records. You must appeal with evidence.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
