Can I lower my advance tax payments?
If your tax bill will be smaller this year, you can ask HMRC to lower your payments on account and keep the cash until it's due.
Your answer
Enter last year's bill and your estimate for this year.
About this calculator
For anyone who pays tax through Self Assessment and makes payments on account: two advance payments towards this year's bill, each half of last year's. It shows whether you have to make them, what they'd be if you lowered them, and what it costs if your estimate is too low.
The bill here is income tax and Class 4 National Insurance after any tax already taken off. Payments on account don't cover Capital Gains Tax, student loan repayments or Class 2 National Insurance, so those are paid with the balancing payment.
What happens to your answers
We don’t keep them. Your answers go to our server to do the sums and aren’t stored or logged. If you copy a link to your answers, they’re in the link itself, so only share it with people you trust.
How it’s worked out
You make payments on account if last year's bill was £1,000 or more, unless more than 80% of your tax was taken off already (through your tax code, CIS or your bank). Each payment is half of last year's bill: one on 31 January in the tax year, one on 31 July after it. The balancing payment, whatever is left, is due the next 31 January.
If this year's bill will be smaller, you can ask HMRC to make each payment half of your estimate instead, online or on form SA303. If your bill turns out bigger, HMRC charges interest on the shortfall from each payment date, at the Bank of England's rate plus 4%. We show the most that could be: interest if the bill turns out as big as last year's.
Worked example
Lowering your payments on account to match this year's bill would free up £6,000 by 31 July 2027.
2026/27 tax year · bills are income tax and Class 4 National Insurance after tax taken off · interest at 7.8% throughout
| Last year's Self Assessment bill | £12,000 |
|---|---|
| Each payment on account: half of £12,000 | £6,000 |
| This year's bill (your estimate) | £6,000 |
| Each payment lowered to half of £6,000 | £3,000 |
| 31 January 2027 payment lower by | + £3,000 |
| 31 July 2027 payment lower by | + £3,000 |
| Cash you could free up | £6,000 |
| Balancing payment on 31 January 2028: £6,000 − £3,000 − £3,000 | £0 |
| If the bill turns out as big as last year's: interest on £3,000 × 7.8% × 365 ÷ 365 days, plus £3,000 × 7.8% × 184 ÷ 365 days | £349.71 |
Worked out using HMRC's published rates for the 2026/27 tax year (6 April 2026 to 5 April 2027), on a yearly basis.
Questions people ask
What if I lower them too far?
You pay interest on the difference from 31 January and 31 July until you pay it. If HMRC thinks your estimate was careless or deliberately low, there can be a penalty too, up to the amount you didn't pay.
Can I lower them after I've paid?
Yes, until 31 January after the tax year ends. HMRC repays the difference or keeps it towards your next bill.
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