Your first Self Assessment tax bill: what you'll pay on 31 January
21 October 2026 · 5 min read · Checked against GOV.UK 21 October 2026
Why the first bill is bigger
When you work for an employer, tax comes off each payslip. When you're self-employed, you pay it in one go after the tax year ends. In your first year, HMRC also asks for the first of two payments on account towards the next year. So your first January bill can be 150% of a year's tax.
Example: a first year at £20,000
| Date | Payment | Amount |
|---|---|---|
| 31 January 2027 | Tax for 2025 to 2026, plus the 1st payment on account | £2,897.70 |
| 31 July 2027 | 2nd payment on account | £965.90 |
If Sam's profit stays the same, that's it for 2026 to 2027. From then on the pattern settles down: two roughly equal payments a year.
What the bill includes
- Income Tax on your profit over the £12,570 personal allowance, at 20% in the basic rate band (Scotland has its own rates).
- Class 4 National Insurance: 6% on profit between £12,570 and £50,270, then 2%.
- Student loan repayments, if you have a loan and your income is over your plan's threshold.
If you also have a job, your wages use up your personal allowance first, so more of your self-employed profit is taxed.
How to pay
- Online or telephone banking: usually arrives the same or next day.
- By debit card online, or through the HMRC app.
- A budget payment plan: regular Direct Debits towards your next bill, if you're up to date.
Pay a few days before 31 January if you can. Some bank transfers, like Bacs, take three working days to arrive.
If you can't pay it all
Don't ignore it. If you owe £30,000 or less, have filed your return and have no other payment plans or tax debts, you can usually set up a monthly payment plan online, up to 60 days after the deadline. You pay interest, but setting one up early can stop the late payment penalties.
Without a plan, a penalty of 5% of the unpaid tax is added at 30 days, again at 6 months and again at 12 months, plus interest. Our guide to tax penalties explains how these are changing under Making Tax Digital.
Making next year easier
The simplest fix is to put aside part of everything you're paid in a separate savings account. For profit in the basic rate band, about a quarter of each payment over your personal allowance usually covers the tax and National Insurance.
Work out your own figures with our self-employed tax calculator, and add the dates to your phone with the deadline calendar. HMRC's guide to paying is on GOV.UK (opens in a new tab).