UK Payment on Account Calculator
Estimate UK Self Assessment payments on account. Calculates the standard two instalments (each 50% of last year’s tax liability) and the total expected payment.
- Page updated:
- Jul 14, 2026
- Tool version:
- v1.1.0
Overview
Estimate UK Self Assessment payments on account. This tool calculates the two standard instalments (each 50% of the previous year's tax liability) and the combined total.
Use this calculator as a quick reference. It is based on HMRC guidance and is intended for illustrative purposes only.
Results
Payment on account — each instalment
$500.00
Total payments on account (both instalments)
$1,000.00
Interpretation note
This estimate assumes standard payments on account (2 instalments of 50%). If your tax liability has changed significantly, or you have reduced payments on account agreed with HMRC, amounts will differ.
How to read the result
- What it means
- The displayed value is an estimate based on your inputs. It represents the calculated scenario under current assumptions, not a guaranteed amount.
- Calculation limits
- The model uses simplified formulas and cannot account for all variables in your specific case (local regulations, personal conditions, temporal changes).
- Next step
- Use the result as a starting point. Adjust parameters to compare scenarios and validate with a professional when needed.
Glossary+−
- Payments on account
Advanced payments towards your next Self Assessment tax bill, normally two instalments each equal to 50% of the previous year’s tax liability.
- Self Assessment tax liability
The total amount of tax due for a tax year after allowances, reliefs and any tax credits are applied.
- Instalment dates
Typical due dates for payments on account are 31 January (first instalment) and 31 July (second instalment).
Key takeaways
This calculator provides an estimate of the two standard payments on account based on your previous year’s Self Assessment tax liability.
Use the results as a reference and verify with HMRC guidance or a tax professional for decisions affecting payments or cash flow.
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Useful links
Worked examples
Example 1 — Standard case
If your last year’s Self Assessment tax liability was £1,000:
Interpretation
You would typically pay £500 on or by 31 January and £500 on or by 31 July (total £1,000), subject to HMRC timings and any adjustments.
Example 2 — Nil liability
If your previous year liability was £0, no payments on account are normally required.
Interpretation
If circumstances have changed, contact HMRC or your adviser to confirm obligations.
Frequently asked questions
How are payments on account calculated?
By default, HMRC requires two instalments, each 50% of the previous year’s Self Assessment tax liability. The instalments are normally due 31 January and 31 July.
Can I reduce payments on account?
You may apply to reduce payments on account if you expect your liability to be lower this year, but you should only do so if you have reasonable grounds. Incorrect reductions can lead to interest or penalties. See HMRC guidance or consult a tax adviser.
Is this a definitive calculation?
No — this calculator provides an estimate based on standard HMRC rules. For personalised advice, consult HMRC or a qualified tax adviser.
Sources & references
- HMRC — Payments on account (Self Assessment): https://www.gov.uk/self-assessment-tax-returns/payments-on-account
- GOV.UK — Paying your Self Assessment tax bill: https://www.gov.uk/pay-self-assessment-tax-bill
Quality & oversight
- Author
- Ugo Candido, MBA
- Maintained by
- Ugo Candido, MBA
- Page updated
- Jul 14, 2026
- Tool version
- v1.1.0