Self Assessment Deadlines & Payments on Account 2026/27
Self Assessment 2026/27: 31 January filing and payment, 31 July second payment on account, how payments on account work, penalties and interest.
2026/27 Self Assessment timeline
| Date | What's due | Who |
|---|---|---|
| 31 Jan 2027 | First payment on account for 2026/27 (with the 2025/26 balancing payment) | Filers who make payments on account |
| 31 Jul 2027 | Second payment on account for 2026/27 | Filers who make payments on account |
| 5 Oct 2027 | Tell HMRC you need to file for 2026/27 | First-time filers, and those who did not need to file for 2025/26 |
| 31 Oct 2027 | Paper return deadline | Paper SA100 filers |
| 30 Dec 2027 | Online filing deadline to have a bill collected through your tax code | Employees and pensioners who want this |
| 31 Jan 2028 | Online filing + 2026/27 balancing payment + 2027/28 first payment on account | All online filers |
| 31 Jul 2028 | 2027/28 second payment on account | Filers who make payments on account |
Dates follow the pattern on gov.uk's Self Assessment deadlines page, applied to the 2026/27 tax year.
Payments on account mechanics
Payments on account are advance payments towards your tax bill. Per gov.uk, you must make them unless:
- last year's Self Assessment bill was less than £1,000; or
- more than 80% of the tax you owed last year was paid outside Self Assessment (for example through your tax code)
Each payment is normally half of last year's bill, including Class 4 National Insurance but not Capital Gains Tax or student loan repayments. The first is due 31 January (the same day as the previous year's balancing payment) and the second 31 July. Any difference is settled at the next 31 January.
3 worked taxpayer scenarios (2026/27 return)
| Taxpayer | Total tax | Paid via PAYE | Paid on account | Balance | 2027/28 POAs? | Due 31 Jan 2028 | Due 31 Jul 2028 |
|---|---|---|---|---|---|---|---|
| Employee with side income, first Self Assessment year No payments on account were made for 2026/27, so the whole balance and the first 2027/28 payment on account fall on 31 January 2028. | £3,500 | £1,200 | £0 | £2,300 | YES | £3,450 | £1,150 |
| Established self-employed, profits rising Paid £3,500 on 31 Jan 2027 and £3,500 on 31 Jul 2027 based on a £7,000 bill for 2025/26. Owes the £1,000 balance plus the first 2027/28 payment on account. | £8,000 | £0 | £7,000 | £1,000 | YES | £5,000 | £4,000 |
| PAYE-heavy with small side income The amount left to pay through Self Assessment is under £1,000, so no payments on account are needed for 2027/28. | £800 | £600 | £0 | £200 | NO | £200 | £0 |
Illustrative figures. Payments on account are worked out on the amount left to pay through Self Assessment after tax deducted at source (TMA 1970 s.59A).
Late filing and late payment penalties
These are the current Self Assessment penalties from gov.uk. They do not apply if you are in Making Tax Digital for Income Tax (see below).
Late filing penalties
- Day 1 after deadline: £100
- After 3 months: £10 a day, up to £900
- After 6 months: a further 5% of the tax due or £300, whichever is greater
- After 12 months: another 5% or £300, whichever is greater
- 12 months late with no tax due: £1,600
Late payment penalties
- 30 days late: 5% of the tax unpaid
- 6 months late: a further 5%
- 12 months late: a further 5%
- Plus interest: Bank Rate + 4 percentage points from the due date, 7.75% from 9 January 2026 (HMRC)
Filing and payment penalties are separate and can both be charged. You can appeal with a reasonable excuse such as a close relative dying shortly before the deadline, an unexpected hospital stay, or HMRC online service problems. gov.uk says a payment failing because you did not have enough money, or not getting a reminder, will not be accepted.
If you are in Making Tax Digital for Income Tax
Sole traders and landlords with qualifying income over £50,000 must use Making Tax Digital for Income Tax from 6 April 2026. Per HMRC's MTD penalties guidance, new penalties replace the ones above from the tax year you join:
- Late submission: a penalty point for each missed deadline, and a £200 penalty once you reach 4 points. There are no penalties for missing a 2026/27 quarterly update deadline.
- Late payment (2026/27): none if paid within 15 days; 3% of the tax owed at day 15; a further 3% at day 30; then 10% a year from day 31. In your first year you have 30 days to pay or arrange a payment plan before penalties start.
- Late payment penalties do not apply to payments on account. Late payment interest works the same way as before.
HMRC also says that from April 2027 the new penalties will apply to everyone who submits a personal Self Assessment tax return.
Time to Pay arrangements
If you cannot pay an overdue bill in full, you may be able to set up a payment plan to pay in monthly instalments, online in some cases or by contacting HMRC.
- HMRC checks the plan is affordable, using details of your income, spending, savings and other tax debts
- If you have savings or assets, HMRC expects you to use them to reduce the debt first
- Interest is still charged on the unpaid tax while you pay
- If your bill is not yet due, a Budget Payment Plan lets you pay towards your next bill weekly or monthly
Related deadlines + planning guides
- UK tax deadlines 2026 - all key dates across SA, CT, VAT, PAYE.
- Self Assessment step-by-step - filing walkthrough.
- UK tax calendar 2026/27 - month-by-month tax events.
- Tax year-end checklist (5 April) - what to do before the tax year closes.
- HMRC penalties guide - full penalty regime across all UK taxes.
- HMRC tax investigation guide - what happens if HMRC opens an enquiry.
- MTD ITSA guide - quarterly reporting for sole traders and landlords over £50,000 from April 2026.
- Side hustle tax calculator - when side income triggers SA registration.
Frequently asked questions
When is the Self Assessment deadline for 2026/27?
For the 2026/27 tax year (6 April 2026 to 5 April 2027), a paper return must reach HMRC by 31 October 2027 and an online return by 31 January 2028. Any tax still owed for 2026/27 is due by 31 January 2028, together with the first payment on account for 2027/28 if you have to make them; the second is due 31 July 2028. If you want an amount under £3,000 collected through your tax code, file online by 30 December 2027. If you register after 5 October 2027, HMRC gives you a filing deadline 3 months from its letter, but the tax is still due on 31 January (gov.uk).
What are payments on account and do I have to pay them?
Payments on account are two advance payments towards your tax bill, each normally half of last year's Self Assessment bill (Income Tax and Class 4 National Insurance), due by 31 January and 31 July. You do not have to make them if last year's bill was under £1,000, or if more than 80% of the tax you owed was paid outside Self Assessment, for example through your tax code. Capital Gains Tax and student loan repayments are not included; they are paid with the balancing payment. If the two payments come to less than the final bill you pay the difference the following 31 January; if more, you can claim a refund (gov.uk; TMA 1970 s.59A).
What is the first-year cash flow shock of going self-employed?
In your first Self Assessment year no payments on account have been made, so on 31 January you owe the whole bill for that year plus the first payment on account for the next year (half the bill). gov.uk's example: a £3,000 bill means £4,500 due on 31 January, then £1,500 on 31 July. With a £10,000 bill that is £15,000 in January and £5,000 in July. Once payments on account are running and profits are stable, the January payment falls back to the balancing payment (if any) plus one payment on account. Pension contributions paid during the tax year reduce the bill; they cannot be made after 5 April for that year.
How are payments on account calculated exactly?
Each payment is 50% of the previous year's Self Assessment liability after tax deducted at source, excluding Capital Gains Tax and student loan repayments (TMA 1970 s.59A; gov.uk). Example: your 2025/26 return, filed by 31 January 2027, shows £12,000 of Income Tax and Class 4 NI still to pay through Self Assessment. Your 2026/27 payments on account are £6,000 on 31 January 2027 and £6,000 on 31 July 2027. When you file the 2026/27 return by 31 January 2028, the £12,000 paid is set against the 2026/27 bill; a shortfall is paid then, along with the first 2027/28 payment on account based on the 2026/27 bill.
Can I reduce my payments on account?
Yes. If you expect this year's bill to be lower - profits or other income falling, more tax relief, or more tax deducted at source - you can apply online or on form SA303, stating the amount you expect. HMRC says you must claim by 31 January after the end of the tax year. If you reduce them too far, you pay the shortfall with interest from the original due dates. A fraudulent or negligent claim to reduce can also bring a penalty of up to the amount that should have been paid (TMA 1970 s.59A(6)).
What happens if I miss the 31 January filing deadline?
Unless you are in Making Tax Digital for Income Tax, the penalties are: £100 immediately; after 3 months, £10 a day up to £900; after 6 months, a further 5% of the tax due or £300, whichever is greater; and after 12 months, another 5% or £300. A return 12 months late with no tax due costs £1,600; with £20,000 due it is £3,000. You can appeal with a reasonable excuse; gov.uk lists a close relative dying shortly before the deadline, an unexpected hospital stay, software failure or HMRC online service issues, but not a lack of money or not getting a reminder.
What about late payment penalties separate from late filing?
Under the current rules, a penalty of 5% of the tax unpaid is charged at 30 days, 6 months and 12 months, on top of late payment interest from the due date. Late payment interest is Bank Rate plus 4 percentage points: 7.75% from 9 January 2026 (HMRC). Example: £5,000 paid 7 months late costs £500 in penalties plus about £226 of interest at that rate. Filing and payment penalties are separate and can both be charged. If you are in Making Tax Digital for Income Tax for 2026/27, different penalties apply: 3% of the tax owed at day 15 and day 30, then 10% a year from day 31.
What is a Time to Pay arrangement?
It is a payment plan agreed with HMRC to clear an overdue tax bill in monthly instalments. Some people can set one up online; otherwise you contact HMRC with details of your income, spending, savings and other tax debts, and HMRC checks the plan is affordable. If you have savings or assets HMRC expects you to use them to reduce the debt first. Interest is still charged on the unpaid tax. If the bill is not yet overdue, a Budget Payment Plan lets you pay towards your next Self Assessment bill weekly or monthly instead (gov.uk).
When do I have to register for Self Assessment?
By 5 October after the end of the tax year, if you need to send a return and have not sent one before (or did not need to last year): for 2026/27, by 5 October 2027. gov.uk says you must send a return if, for example, you were a sole trader with income over £1,000, a partner in a partnership, had Capital Gains Tax to pay, or owe the High Income Child Benefit Charge and do not pay it through PAYE; untaxed income such as rent, savings interest, dividends or foreign income may also require one. HMRC usually posts your UTR around 15 days after you register. A late registration can bring a failure-to-notify penalty of up to 30% of the unpaid tax (non-deliberate), 70% (deliberate) or 100% (deliberate and concealed), before reductions for disclosure (FA 2008 Sch 41).
Can I file Self Assessment myself or do I need an accountant?
Many people file their own return online using HMRC's free online service. An accountant or tax adviser is more often used for partnerships, several capital gains or property sales, overseas income, or where income interacts with things like the High Income Child Benefit Charge, the Personal Allowance taper or pension allowances. A limited company's own Corporation Tax return (CT600) is separate from a director's personal Self Assessment return. From 6 April 2026, sole traders and landlords with qualifying income over £50,000 must use software for Making Tax Digital for Income Tax.
How long does HMRC have to enquire into my Self Assessment return?
For a return filed on time, HMRC can open an enquiry up to 12 months after the day it received the return; for a late return, up to the quarter day (31 January, 30 April, 31 July or 31 October) after the first anniversary of filing (TMA 1970 s.9A). Separately, HMRC can raise a discovery assessment up to 4 years after the end of the tax year (5 April 2031 for 2026/27), 6 years where the loss of tax was careless (5 April 2033) and 20 years where it was deliberate (5 April 2047) (TMA 1970 ss.34 and 36). If you are self-employed, keep records for at least 5 years after the 31 January filing deadline (gov.uk).
What if I overpaid - can I claim a refund?
If your return shows you paid too much, for example because payments on account exceeded the final bill, you can claim the overpayment back from HMRC. HMRC pays repayment interest at Bank Rate minus 1 percentage point, with a 0.5% floor: 2.75% from 9 January 2026. If you are not in Self Assessment, gov.uk has separate routes, for example for tax taken from savings interest or payment protection insurance (PPI). A claim for overpaid tax is generally limited to 4 years after the end of the tax year, so a 2022/23 claim must be made by 5 April 2027.