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The short answer
UK freelancers pay Self Assessment tax on 31 January (the balance for the last tax year plus a first payment on account for the current one) and on 31 July (the second payment on account). Each payment on account is half of the previous year's bill, so a first-year freelancer can owe 150% of a year's tax in one January. Late payment brings 5% penalties at 30 days, 6 months and 12 months, plus interest.
For a freelancer paid by Nigerian clients, the hard part of UK tax is rarely the return itself. It is the cash: knowing what leaves your account and when, especially when income arrives in uneven lumps and sometimes in naira. Two dates a year carry almost all of it.
The dates in one table
For the 2025-26 tax year (6 April 2025 to 5 April 2026), GOV.UK lists these deadlines:
| Date | What is due |
|---|---|
| 31 October 2026 | Paper return for 2025-26 |
| 30 December 2026 | Online return, if you want tax collected through your PAYE tax code |
| 31 January 2027 | Online return for 2025-26; balancing payment for 2025-26; first payment on account for 2026-27 |
| 31 July 2027 | Second payment on account for 2026-27 |
The tax-code route needs a PAYE income to collect through, so most freelancers with only Nigerian clients will pay directly. GOV.UK's deadlines page states the 31 January and 31 July payment dates; check it each year, because the tax year in the dates changes but the pattern does not.
How payments on account work
Payments on account are advance payments towards next year's bill. GOV.UK explains that each one is half of your previous year's tax bill, they include Class 4 National Insurance, and they are due on 31 January and 31 July. You do not have to make them if your last bill was under £1,000, or if more than 80% of your tax was already deducted at source (for example through PAYE on a job).
If the payments on account turn out to be more than your actual bill, the excess comes back to you or reduces the next payment. If they are less, you pay the difference as the balancing payment on the following 31 January.
Why the first year is the expensive one
GOV.UK gives its own example: a 2023-24 bill of £3,000 with no payments on account made before, so £4,500 was due on 31 January 2025 (the £3,000 bill plus a £1,500 first payment on account for 2024-25), and £1,500 on 31 July 2025.
Worked example (illustrative). Tolu started freelancing for Lagos agencies in May 2025. Her 2025-26 Self Assessment shows £4,000 of income tax and Class 4 NI.
- 31 January 2027: £4,000 balance for 2025-26 + £2,000 first payment on account for 2026-27 = £6,000.
- 31 July 2027: second payment on account for 2026-27 = £2,000.
- If her 2026-27 bill turns out to be £5,000, she owes a balancing payment of £1,000 on 31 January 2028 (£5,000 minus the £4,000 already paid on account), plus the first payment on account for 2027-28.
If your income is falling, you can ask HMRC to reduce payments on account, online or with form SA303. GOV.UK warns that if you reduce them too far you will be charged interest on the shortfall.
Paying late: penalties and interest
GOV.UK's penalties page sets out a late payment penalty of 5% of the unpaid tax at 30 days, again at 6 months and again at 12 months, with interest on top. Late filing is separate: £100 at first, then daily penalties after three months and further charges after six and twelve months. If you registered late (after 5 October following the tax year) and have not paid everything by 31 January, there can also be a failure-to-notify penalty.
If you know you cannot pay in full, the GOV.UK payment pages point to a Time to Pay arrangement. Contacting HMRC before the deadline is better than after it.
Spreading the cost through the year
HMRC's Budget Payment Plan lets you pay weekly or monthly by Direct Debit towards your next bill, if you are up to date with your last one. You set it up in your online account, choose the amount, and can pause payments for up to six months. If the plan does not cover the whole bill, you pay the difference at the deadline. Your payment reference is your 10-digit UTR followed by the letter K.
What to check first
- Your UTR and online account work (register by 5 October after your first tax year if you have not; see registering as self-employed with Nigerian client income).
- Whether you will owe payments on account (last bill £1,000 or more, and under 80% taxed at source).
- What 150% of your expected bill looks like in your first January.
- Whether you will join Making Tax Digital for Income Tax, which adds quarterly updates but does not change these payment dates (MTD for freelancers).
Where Pryme fits
A Pryme Business Account keeps GBP and naira receipts in the currencies they arrived in, so you can hold a sterling balance for 31 January and 31 July and Swap naira only when you decide. The Finance agent can prepare a list of upcoming tax dates and the amounts you set aside, for you to review; nothing moves without approval. For the first-year cash squeeze, see payments on account in your first year.
Questions people ask
When do freelancers pay tax in the UK?
On 31 January (balancing payment plus first payment on account) and 31 July (second payment on account), under GOV.UK's Self Assessment deadlines.
Why is my first Self Assessment bill so big?
Because in the first January you pay the whole of last year's tax plus half of it again as the first payment on account for the current year.
Do I have to make payments on account?
Not if your last bill was under £1,000 or more than 80% of your tax was deducted at source.
What happens if I pay my tax bill late?
Interest runs from the deadline, and penalties of 5% of the unpaid tax apply at 30 days, 6 months and 12 months.
Sources
- GOV.UK: Self Assessment tax return deadlines · accessed Oct 2026
- GOV.UK: Understanding your Self Assessment tax bill, payments on account · accessed Oct 2026
- GOV.UK: Self Assessment tax return penalties · accessed Oct 2026
- GOV.UK: Pay your Self Assessment tax bill, pay weekly or monthly (updated 20 Oct 2026) · accessed Oct 2026
- GOV.UK: Register for Self Assessment (updated 8 Oct 2026) · accessed Oct 2026
This article is general information, not financial, legal or tax advice. Products described are provided under the terms on this site and are subject to regulation and eligibility.