2025-26 tax return and payment due 31 January 2027
Your 31 January 2027 Self Assessment bill — worked out, with every figure next to its HMRC box
Work out your 2025-26 Self Assessment bill due 31 January 2027: tax, Class 4, student loan and child benefit charge, the balancing payment plus your first 2026-27 payment on account, and every figure next to its SA103S, SA105 and SA100 2026 box. No account — your numbers stay in your browser.
- The whole January bill, not just the tax. The 2025-26 balancing payment plus your first 2026-27 payment on account in one figure, the 31 July 2027 payment, both tests that decide whether you need payments on account at all, and HMRC's 7.75% late interest per day.
- Box numbers from HMRC's own 2025-26 forms. SA103S 2026, SA105 2026 (boxes 5 to 19 are no longer used), SA102 and SA100 2026 — all 50 box labels in our list are checked against the HMRC PDFs.
- Every month (Pro): add that month's income and costs, or import your bank CSV, and see what to set aside a month for 31 January 2028 on 2026-27 rates (dividend tax rises to 10.75% and 35.75%, Scottish bands move) — and whether you can reduce your 2026-27 payments on account.
- No account. Your numbers stay in this browser. Nothing is uploaded.
Free: the full 2025-26 calculation and box list. Pro: $5.99/month or $39/year.
1Your 2025-26 figures (6 April 2025 to 5 April 2026)
Whole pounds are fine. Leave anything that does not apply empty. Everything is saved in this browser as you type.
2Monthly tracker for 2026-27 — what to set aside for 31 January 2028
Log each month's income and costs (or import a bank CSV). Every entry updates your 2026-27 estimate on 2026-27 rates and the amount to put aside each month for every payment still to come.
Free vs Pro
Free
- The full 2025-26 calculation: income tax (Scotland too), Class 4, student loans, child benefit charge, allowances picked for you
- Your 31 January 2027 and 31 July 2027 amounts, the payments-on-account tests, late interest, and the box list
- Up to 20 entries in the 2026-27 tracker · export and backup always free
Pro — $5.99/month or $39/year
- Unlimited 2026-27 entries and bank CSV import (duplicates skipped, costs sorted into HMRC boxes)
- Your 2026-27 estimate on 2026-27 rates, refreshed with every entry, and the amount to set aside each month for 31 January 2027, 31 July 2027 and 31 January 2028
- Reduce-payments-on-account check: when your 2026-27 figures run lower, the reduced amount to ask HMRC for and the cash it keeps in January and July
- Calendar file with every payment date and a monthly reminder to log
Subscriptions renew until you cancel in your Whop account. If you cancel, your entries stay in this browser and still export; the Pro estimate, CSV import and entries past 20 lock. After paying you get a licence key; the link on the thank-you page opens Pro here.
Questions
Why is my January bill bigger than my tax?
If your 2025-26 bill after tax taken at source is £1,000 or more, and less than 80% of it was taken at source, HMRC also asks for a first payment on account for 2026-27 on 31 January 2027 — half of this year's figure — and the second half on 31 July 2027. Class 2, student loans and capital gains are never part of it.
Can I pay less on account?
Yes, if you expect 2026-27 to be lower. Ask HMRC in your online account or on form SA303. If you reduce too far, HMRC charges interest on the shortfall from each due date.
Where does my data go?
Nowhere. It is kept in this browser's storage. The only request this page makes on its own is the licence check, which sends the key you typed.
What does it not cover?
Capital gains, foreign income, partnerships, trusts, the high-income pension annual allowance charge, and losses set against other income. For capital gains use the separate calculator linked below.
Is this tax advice?
No. It is a calculator using HMRC's published 2025-26 and 2026-27 rates. Check the figures in your HMRC online account before you pay.