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Payments on account calculator

Work out your Self Assessment balancing payment and payments on account for 31 January and 31 July, using GOV.UK's rules. Runs in your browser; nothing is stored.

How payments on account work

Payments on account are payments towards your next tax bill, including Class 4 National Insurance if you're self-employed. Each is usually half of the tax you owed for the previous year, due by midnight on 31 January and 31 July. You don't have to make them if your bill was less than £1,000, or if you paid more than 80% of your tax outside Self Assessment, for example through your tax code (GOV.UK).

The balancing payment is what's left after the payments on account you made, due by 31 January the following year, and it also includes Capital Gains Tax and student loan repayments. GOV.UK's example: a £3,000 bill with £1,800 paid on account means a £1,200 balancing payment plus a £1,500 first payment on account, £2,700 in January, then £1,500 in July.

The first January after you start trading is often the biggest shock: the whole first-year bill plus half of it again. Estimate your bill with the self-employed tax calculator and set money aside monthly. Keep records in FreeAgent, Xero or Zoho Books, and check when Making Tax Digital applies.

Based on GOV.UK, checked 15 October 2026. Your Self Assessment statement shows your actual amounts.

Questions

What are payments on account?

Advance payments towards your next Self Assessment bill, each usually half of last year's tax, due 31 January and 31 July.

Who doesn't have to make payments on account?

People whose last bill was under £1,000, or who paid more than 80% of their tax outside Self Assessment.

Do payments on account include Class 4 National Insurance?

Yes. Student loan repayments and Capital Gains Tax are paid in the balancing payment instead.

Why is my first January bill so big?

You may owe the whole first year's bill plus the first payment on account for the next year.