Taxation (UK) · The time limits for the submission of information, claims and payment of tax, including payments on account

Income Tax Filing Deadlines and Payments on Account

Updated 11 October 2026 · Fact-checked

Self-assessment returns are due by 31 October after the tax year end for paper and 31 January for online filing. Payments on account are two equal instalments, each 50% of last year's income tax and Class 4 NIC not collected at source, due 31 January and 31 July. The balance is due the next 31 January.

Understand Income Tax Filing Deadlines and Payments on Account

Self-assessment makes you responsible for telling HMRC about your income and paying the tax. Two things matter: when you file the return and when you pay. They are different dates, and exam questions test whether you can keep them apart.

For filing, the tax year ends on 5 April. A paper return is due by 31 October following the end of the tax year. An online return is due by 31 January following the end of the tax year. If you need to file but have not received a return, you must tell HMRC that you are chargeable to tax by 5 October following the end of the tax year.

For payment, HMRC does not wait until the year is over. If you are self-employed or have large untaxed income, you pay payments on account during the year. These are advance payments based on last year's bill. They are two equal instalments due on 31 January in the tax year and 31 July after the tax year. The first is due before the year has even ended.

After the year ends, your actual liability is known. You compare it with the payments on account you made. The difference is the balancing payment (or a repayment), due on 31 January following the tax year, the same day as the online filing deadline.

Payments on account cover income tax and Class 4 NIC. They do not cover capital gains tax, which is paid separately, and they only apply to the tax not already collected at source, such as through PAYE.

Key rules to remember

Relevant amount for payments on account: Previous year's income tax liability − tax deducted at source (e.g. PAYE) + Class 4 NIC; Use the prior year's figures. Do not include capital gains tax. Add Class 4 NIC only after the exemption tests have been applied to income tax.
Each payment on account: Relevant amount × 50%; Two equal instalments.
Payment on account due dates: 31 January in the tax year; 31 July following the tax year; For 2026–27: 31 January 2027 and 31 July 2027.
Balancing payment: Actual liability for the year − payments on account made; Due 31 January following the tax year. If negative, it is a repayment.
When no payments on account are required: Income tax liability − tax deducted at source is less than £1,000, or more than 80% of the income tax liability was met by deduction at source; Both tests use the previous year's income tax only. Class 4 NIC is not part of either test.
Return filing dates: Paper: 31 October following the tax year; online: 31 January following the tax year; Notify HMRC of chargeability by 5 October following the end of the tax year.
Interest on underpaid tax: 8.50% (assumed rate given in the ACCA tax rates); Runs from the due date of each payment to the date of payment.

How to solve Income Tax Filing Deadlines and Payments on Account questions

Use this method for any question on filing dates and payments on account.

1Identify the tax year and write its dates. The year ends on 5 April, so 2026–27 ends on 5 April 2027.
2Decide what is being asked: a filing date, a payment date, a payment on account amount, or a balancing payment.
3For filing, check paper or online. Paper is 31 October after the year end, online is 31 January after it.
4For payments on account, take the previous year's income tax liability and deduct tax collected at source. Check this figure is not under £1,000 and that tax collected at source is not more than 80% of the income tax liability. Class 4 NIC is left out of both tests.
5If payments are required, add Class 4 NIC to the income tax left after deduction at source. This is the relevant amount. Halve it, and write both dates beside the two instalments.
6For the balancing payment, compute the actual current-year figure on the same basis and subtract the payments on account made. Capital gains tax is paid separately, so keep it out of this calculation.
7If a reduction claim is involved, work out the correct payments on account and compare them with those paid. The shortfall bears interest from the original due dates.

Quickest way: Two lines of working

When to use it: For multiple-choice questions and short parts of constructed-response questions where you need the amount and dates fast.

Line 1: Last year's income tax − tax deducted at source. Check this is at least £1,000 and that tax at source is not above 80% of the income tax liability. Then add Class 4 NIC to get the relevant amount.
Line 2: Relevant amount ÷ 2 = each payment on account. Dates are 31 January and 31 July, then the balancing payment next 31 January.
Cross-check the dates: tax year 20X6–X7 means payments on account in January 20X7 and July 20X7, with the balancing payment and online return on 31 January 20X8.

Common mistakes in Income Tax Filing Deadlines and Payments on Account

Basing payments on account on the current year's liability
Students think the payments are towards this year's bill, so they use this year's figures.
Fix: Always use the previous year's figures. The current year only matters for the balancing payment.
Forgetting to deduct tax collected at source
Students use the total income tax liability without thinking about PAYE or other deductions.
Fix: Take the total liability, then deduct tax already collected at source. Only the rest goes into the payments on account base.
Including capital gains tax in payments on account
Students treat self-assessment as one bill.
Fix: Payments on account cover income tax and Class 4 NIC only. Capital gains tax is a separate payment.
Mixing up the filing and payment dates
31 January appears in several places: the online filing date, the first payment on account and the balancing payment.
Fix: Write the three 31 January items separately. Treat 31 October as paper filing only, and 31 July as the second payment on account.
Applying the exemption tests to the current year
Students look at this year's figures when deciding whether payments on account are needed.
Fix: Both the £1,000 test and the 80% test look at the previous year.
Treating a reduction claim as free of consequences
Students think any reduction claim is safe once it is made.
Fix: If the claim reduces payments too far, the shortfall carries interest from the original due dates. Penalties may apply if the claim was made carelessly or deliberately.

Worked examples

Example 1

Priya is self-employed. For 2025–26 her income tax liability was £14,000, of which £3,000 was collected under PAYE, and her Class 4 NIC was £2,000. Calculate her payments on account for 2026–27 and state the due dates.

Show the solution

Income tax liability less tax deducted at source = £14,000 − £3,000 = £11,000.
Check the tests on income tax only: £11,000 is not below £1,000. The £3,000 collected at source is about 21% of her £14,000 liability, well below 80%. Payments on account are required.
Add Class 4 NIC: relevant amount = £11,000 + £2,000 = £13,000.
Each payment = £13,000 × 50% = £6,500.
Due dates: 31 January 2027 and 31 July 2027.

Answer: Two payments on account of £6,500 each, due 31 January 2027 and 31 July 2027.

Example 2

Using Priya's figures above, her actual 2026–27 income tax after PAYE plus Class 4 NIC is £16,000. State the balancing payment and its due date, and the latest dates to file her 2026–27 return on paper and online.

Show the solution

Actual 2026–27 liability for this purpose = £16,000.
Payments on account made = £6,500 × 2 = £13,000.
Balancing payment = £16,000 − £13,000 = £3,000.
Due date for the balancing payment is 31 January 2028.
Filing: the 2026–27 tax year ends on 5 April 2027. The paper return is due 31 October 2027 and the online return 31 January 2028.

Answer: Balancing payment £3,000 due 31 January 2028. Paper return due 31 October 2027; online return due 31 January 2028.

Exam tips

Write the dates down in full, including the year. Section A questions often hinge on getting the tax year and the date right.
Use the previous year's liability for payments on account and the current year's liability for the balancing payment. Label them on your working.
Keep capital gains tax out of the payments on account calculation. Examiners include a gain in the scenario to see whether you leave it out.
In constructed-response answers, show the relevant amount, then the halving, then the dates. Marks are awarded for each step, so do not give only a final number.
For reduction claims, read for the key detail: is the claim honest and reasonable? If the reduction proves too large, interest is charged on the shortfall.

Practice questions from The time limits for the submission of information, claims and payment of tax, including payments on account

Income Tax Filing Deadlines and Payments on Account: frequently asked questions

When are payments on account due?

The first is due on 31 January in the tax year and the second on 31 July following the tax year. Each is 50% of the relevant amount from the previous year. The balancing payment follows on 31 January after the year end.

How are payments on account calculated?

Take the previous year's income tax liability, deduct tax collected at source, and add Class 4 NIC. Halve the result to get each instalment. Capital gains tax is not included.

When can payments on account be reduced?

You can claim to reduce them if you expect the current year's liability to be lower than the previous year's. If you reduce them too far, the shortfall bears interest from the original due dates. Penalties can apply if the claim was careless or deliberate.

What is the difference between the paper and online filing deadline?

A paper return is due by 31 October following the end of the tax year. An online return is due by 31 January following the end of the tax year. The payment deadline for the balancing payment is 31 January either way.

Do I always have to make payments on account?

No. They are not required if the previous year's income tax liability less tax deducted at source is below £1,000, or if more than 80% of the previous year's income tax liability was met at source. Class 4 NIC is not part of either test.