Deadlines & penalties · 2025/26
31 January2027.
File your 2025/26 return online and pay what you owe by midnight on 31 January 2027, or HMRC's penalties start automatically.
Key dates
The 2025/26timeline.
6 April 2025
Tax year starts
The 2025/26 tax year begins. Income from this date onwards falls into this return.
5 April 2026
Tax year ends
The 2025/26 tax year closes. Gather your documents and start preparing your return.
5 October 2026Next deadline
Registration deadline
If you're new to Self Assessment, you must register with HMRC by this date.
31 October 2026
Paper filing deadline
Last day to submit a paper tax return. File online instead for an extra 3 months.
31 January 2027
Online filing & payment deadline
File your online return AND pay any tax owed by midnight. This is the big one.
31 July 2027
2nd payment on account
If you make payments on account, the second instalment for 2025/26 is due.
Penalties
Late costsmore than £49.
Late filing
- 1 day late£100 fixed penalty£100
- 3 months late£10/day for 90 days£1,000
- 6 months late5% of tax due or £300 (whichever is greater)£1,300+
- 12 months lateFurther 5% or £300 (whichever is greater)£1,600+
Late payment
- 30 days late5% of unpaid tax
- 6 months lateFurther 5% of unpaid tax
- 12 months lateFurther 5% of unpaid tax
Plus interest at the Bank of England base rate + 2.5%, from the due date until you pay.
The £100 penalty applies even if you owe no tax. If you don't need to file, tell HMRC to remove you from Self Assessment instead.
Stay on track
How to avoidpenalties.
- 1
Register for Self Assessment early — don't wait until the deadline approaches.
- 2
Use online filing (deadline is 31 January, 3 months later than paper).
- 3
Set up a payment plan with HMRC if you can't pay in full — contact them before the deadline.
- 4
Start gathering documents as soon as the tax year ends in April.
- 5
Use TaxGo to prepare your return — drop your documents in and we handle the boring bits.
Common questions
DeadlineFAQs.
- What happens if I file one day late?
- You'll receive an automatic £100 penalty from HMRC, even if you owe no tax or have already paid what you owe. This penalty applies from 1 February if you miss the 31 January online filing deadline.
- Do I still get penalised if I owe no tax?
- Yes. The £100 late filing penalty applies regardless of whether you owe tax. If you don't need to file a return, you should tell HMRC to remove you from Self Assessment rather than simply not filing.
- Can I set up a payment plan with HMRC?
- Yes. If you owe less than £30,000 and are within 60 days of the payment deadline, you can set up a Time to Pay arrangement online through your HMRC account. For larger amounts, call HMRC's Payment Support Service on 0300 200 3835.
- When can I start filing for 2025/26?
- You can file your 2025/26 Self Assessment tax return from 6 April 2026 onwards. HMRC's online service typically opens in April. Filing early doesn't mean you have to pay early — payment is still due by 31 January 2027.
- What if I haven't received my UTR yet?
- If you've registered but haven't received your UTR, call HMRC on 0300 200 3310. It usually takes 10 working days (21 days if abroad). You cannot file without a UTR, so register early to avoid delays.
- Can I file early and pay later?
- Yes. You can submit your tax return as soon as the tax year ends (from 6 April 2026), but payment isn't due until 31 January 2027. Filing early gives you certainty about what you owe and more time to budget.
- What interest is charged on late payments?
- HMRC charges interest on late payments at the Bank of England base rate plus 2.5%. Interest is calculated from the due date until the date you pay. This is in addition to any late payment penalties.
- Can I appeal a penalty?
- Yes. You can appeal within 30 days if you have a reasonable excuse, such as a serious illness, bereavement, or HMRC service issues. You can appeal online through your HMRC account or by writing to them.
Don’t waituntil January.
Start free. You only pay when your return is ready to approve.