UK money
Self Assessment and payments on account
Income tax, Class 4, the balancing payment, and the January and July dates.
Last updated: October 2026
How to use it
- Enter self-employed profit for 2025/26, after allowable expenses. Add employment or other income if you have it.
- Enter tax already taken through PAYE, and any payments on account you have already made for this year.
- Choose a student loan plan if one applies. Read what is due on 31 January 2027 and 31 July 2027.
How it's calculated
Income tax uses the rest-of-UK bands for 2025/26: Personal Allowance £12,570, basic rate 20% on the next £37,700, higher rate 40%, additional rate 45%, and the allowance reduced by £1 for every £2 of income over £100,000. Scottish income tax is not calculated. Savings and dividend rates are not calculated: other income is taxed as non-savings income. Marriage Allowance is not applied.
Class 4 National Insurance is 6% on profits between £12,570 and £50,270 and 2% above that. Class 2 is treated as paid when profits are at least £6,845.00. Below that, voluntary Class 2 is £3.50 a week for 52 weeks if you tick it. Payments on account are half of income tax plus Class 4, minus PAYE, unless that amount is under £1,000.00 or more than 80% of the income tax and Class 4 was paid at source. Student loan and Class 2 sit on the balancing payment. They are not split into the two payments on account.
Worked examples
Profit of £20,000 and nothing else: income tax £1,486.00, Class 4 £445.80. Class 2 is treated as paid. Each payment on account is £965.90. With nothing already paid, 31 January 2027 is £2,897.70 (the balancing payment plus the first payment on account) and 31 July 2027 is £965.90.
Profit of £15,000: income tax £486.00 and Class 4 £145.80, together £631.80. That is under £1,000, so there are no payments on account. 31 January 2027 is the balancing payment of £631.80. 31 July 2027 is £0.00.
Profit of £60,000 with £12,000 already paid through PAYE: income tax £11,432.00, Class 4 £2,456.60. More than 80% of that tax was paid at source and the remainder is at least £1,000, so payments on account are not required. The balancing payment is £1,888.60.
Sources
GOV.UK: income tax rates, HMRC: National Insurance rates, Class 2 and Class 4 for 2025 to 2026, GOV.UK: payments on account, Student Loans Company: 2025/26 repayment thresholds.
I check these figures after each Budget or Finance Act and when a rate changes. The calculation runs in this browser. Nothing you type is stored or uploaded. Corrections: [email protected].
Questions
When is the 2025/26 return due?
The online return and the balancing payment are due by midnight on 31 January 2027. The second payment on account, if one is due, is due by midnight on 31 July 2027.
Do I have to make payments on account?
GOV.UK says you do, unless last year’s tax bill was less than £1,000, or more than 80% of the tax you owed was paid outside Self Assessment. This page tests those two rules on the figures you type.
Is Class 2 still a charge?
For 2025/26, Class 2 is treated as paid once profits reach £6,845. You can choose to pay £3.50 a week if profits are below that. The 2026/27 small-profits threshold and weekly rate are higher, and this page does not use them.
Which student loans are included?
Plan 1, Plan 2, Plan 4 and the Postgraduate Loan, at the 2025/26 annual thresholds. Plan 5 repayments start in 2026/27, so Plan 5 is not on this page. The repayment is an annual percentage, not the payroll pound-rounding used on a payslip.
Can I reduce a payment on account?
Yes, through your HMRC online account or form SA303, if you expect the next bill to be lower. If you reduce it too far, HMRC charges interest on the difference. This page does not send that claim.