What will actually leave my account in January?
The number at the bottom of your tax calculation is rarely the number HMRC collects. In your first year over the £1,000 threshold, the January payment is half as much again — the year's tax plus the first instalment towards next year. Enter your bill to see both dates and both amounts. Nothing is stored and you do not need an account.
The £6,000 bill that costs £9,000
A freelancer finishes their first full year of self-employment owing £6,000 in Income Tax and Class 4 National Insurance. They budget £6,000 for 31 January. HMRC asks for £9,000.
The extra £3,000 is the first payment on account towards the year that is, by that January, already nine months old. A second £3,000 follows on 31 July. In total they hand over £12,000 across seven months, having earned one year's profit — and the cash-flow shock, not the tax itself, is what catches people out.
It settles down after that. The following January, those two £3,000 instalments are deducted from the new bill, so only the difference is due alongside the next first instalment. The painful year is the first one.
Common questions
What are payments on account?
They are advance payments towards next year's tax bill, collected in two instalments. HMRC assumes next year will look like this year, so each instalment is half of your current Self Assessment liability. The first is due on 31 January — the same day as the balance of the current year's bill — and the second on 31 July.
Why is my January tax bill 50% higher than the tax I owe?
Because two things fall due on the same date: the balancing payment for the year that has ended, and the first payment on account for the year already running. If you owe £6,000 for the year just gone and made no payments on account towards it, you pay £6,000 plus £3,000 — £9,000 — on 31 January, then a further £3,000 on 31 July.
Do I have to make payments on account?
Not if the tax you owe through Self Assessment is under £1,000, and not if more than 80% of the tax you owed for the year was already collected at source — through a PAYE tax code, CIS deductions, or tax taken off at source. If either applies, you settle the bill in one payment and nothing is due in July.
Can I reduce my payments on account?
Yes. If you expect the coming year to be worse than the last one, you can apply to HMRC to reduce both instalments. The risk is that if you reduce them below what you actually end up owing, HMRC charges interest on the shortfall from the date each instalment was originally due — so reduce them on evidence, not optimism.
Are Capital Gains Tax and student loan repayments included?
No. Both are collected through Self Assessment but neither counts towards the payment-on-account calculation, so they fall due in full with the balancing payment on 31 January rather than being spread across the two instalments.
What happens in my second year of Self Assessment?
The two payments on account you made during the year are deducted from that year's bill, leaving a smaller balancing payment — or a refund if they overshot. On top of that balancing payment, the first instalment towards the following year falls due on the same 31 January. The cycle repeats, which is why the second January is usually less of a shock than the first.
Other free tools
This tool applies HMRC's published payments on account rules, last reviewed on 5 September 2026. It is not tax advice and does not account for individual circumstances such as Capital Gains Tax, student loan repayments, Class 2 National Insurance, or a claim to reduce your instalments. Check HMRC's own guidance or speak to an accountant if you are unsure. See where EasyTax stands with HMRC.