HMRC penalties
UK HMRC Late Payment Interest & Penalties Calculator (2026).
Estimate HMRC late payment interest at 8.5% per annum and fixed penalties for late Self Assessment, Corporation Tax, VAT or PAYE filings and payments.
HMRC charges late-payment interest at 8.5% a year on tax paid late, accruing daily from the due date. For Self-Assessment, filing late triggers an immediate £100 penalty, then £10 a day after three months, plus 5% surcharges on the unpaid tax at 6 and 12 months. Corporation Tax, VAT and PAYE have their own late-payment penalties. This calculator estimates the total interest and penalties for 2026.
Total now owed
£5,385
Includes tax, penalties and late payment interest
Additional cost
£384.93
- Filing penalty
- £100
- Payment penalty
- £250
- Interest charged
- £35
Daily interest accruing
£1.16/day
Using the rate reviewed on 1 January 2026.
Full breakdown
- Tax owed£5,000.00
- + Filing penalty£100.00
- + Late payment penalty£250.00
- + Interest (30 days at 8.5%)£34.93
- = Total owed£5,384.93
This is an estimate for guidance only. HMRC's actual assessment may differ. Contact Countify immediately if you have an overdue tax liability.
Source: gov.uk HMRC interest rates. Rates verified 1 January 2026.
Related calculators
Keep planning.
Deadlines
Tax Deadline Checker
Self-Assessment, VAT, CT600, P11D and Confirmation Statement — late-filing exposure.
Self-Employed NI
Self-Employed NI Calculator
Class 2 and Class 4 NI for sole traders. 6% / 2% bands handled automatically.
Corporation Tax
Corporation Tax Estimator
Estimate CT600 with marginal relief between £50k and £250k profit.
Questions
Frequently asked
questions.
HMRC charges 8.5% per annum simple interest from the payment due date. The rate is reviewed periodically by HMRC.
Yes, if you have a reasonable excuse such as serious illness, bereavement or HMRC delays. Countify can prepare and submit a penalty appeal.
The Self Assessment late filing penalty is £100 immediately, plus £10 per day after 3 months up to £900, plus 5% of tax or £300 after 6 and 12 months.
Penalties are fixed amounts at set milestones. Interest is charged at a simple daily rate on the outstanding tax. They do not compound on each other.
As soon as possible. Every day adds to the interest charge, and even a part-payment reduces the amount on which interest accrues.
Get started
Take control of your
numbers today.
Free, no-obligation consultation. We agree the fee upfront — no surprises.
- Expert advice
- Fixed fees
- Fast response