Guides › How to Reduce Payments on Account: Online or SA303
How to Reduce Payments on Account: Online or SA303
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Not tax advice. Information only. Check GOV.UK or a qualified adviser for your own situation. Dates and rules were last checked against GOV.UK on 17 October 2026 and can change.
Short answer: GOV.UK says that if you know the tax you owe is going to be lower than last year, you can ask HMRC to reduce your payments on account, online or by post. You must include the amount you expect to owe.
Online
Sign in to your online account → view your latest Self Assessment return → select Reduce payments on account.
By post
Send form SA303 to your tax office.
What to put
The amount you expect to pay: HMRC uses it to work out your new payments on account. Base it on your records, not a guess.
The risk
GOV.UK says that if you reduce your payments and your bill turns out higher than expected, you'll be charged interest on the difference. Check the interest rates page for current rates; we don't quote one.
When reducing may be relevant
- Your income dropped (our example: a made-up case where last year's profit was high and this year's is much lower).
- Don't use reduction if you're unsure; talk to a qualified adviser.
Before you reduce
- Check what you've already been asked to pay on your statement.
- Work out your expected tax for the year from your records.
- Note the 31 January and 31 July deadlines.
FAQ
Does reducing remove my balancing payment? No; any tax owed beyond payments made is still due.
Can I undo a reduction? We did not find this on the pages read.
What we could not verify
- Whether a reduction can be changed later.
- The current interest rate.
Sources (GOV.UK)
- GOV.UK, Understand your Self Assessment bill: Payments on account — https://www.gov.uk/understand-self-assessment-bill/payments-on-account (read 17 October 2026)
- GOV.UK, Pay your Self Assessment tax bill — https://www.gov.uk/pay-self-assessment-tax-bill (read 17 October 2026)
Deadlines calendar → Penalty estimator →
Not tax advice. See the disclosure.