Updated for 2026/27 · No signup · Estimate only, not financial advice
If your last Self Assessment tax bill was over £1,000 (and less than 80% was collected via PAYE), HMRC usually requires two Payments on Account of 50% each towards next year's bill — due 31 January and 31 July.
Worked example
If your Self Assessment bill for the year was £6,000, you'd typically owe that £6,000 plus a first Payment on Account of £3,000 (50%) by 31 January, then a second Payment on Account of £3,000 by 31 July — a total of £9,000 due in January.
Common mistakes
Forgetting Payments on Account exist and being caught out by a much larger January bill than expected.
Not applying to reduce Payments on Account when income has genuinely dropped — you can ask HMRC to reduce them if you expect to earn less.
Missing the 31 July second instalment, which accrues interest just like the January payment.
Anyone whose Self Assessment tax bill was over £1,000, unless more than 80% of their tax was already collected at source (for example through PAYE).
When are Payments on Account due?
The first instalment is due 31 January (alongside your balancing payment), and the second is due 31 July, each equal to 50% of your previous year's tax bill.
Can I reduce my Payments on Account?
Yes — if you genuinely expect to earn less this year, you can apply to HMRC to reduce your Payments on Account. Reducing them too far when you shouldn't can trigger interest charges later.