HMRC Interest & Penalties Calculator 2026/27
Calculate the interest and penalties on late tax payments. See how much you'll owe HMRC including daily interest at 7.75% and penalty charges.
30 days late
First penalty
6 months late
Second penalty
12 months late
Third penalty
What is HMRC's late payment interest rate?
HMRC charges late payment interest at the Bank of England base rate plus 2.5%. As of 2026/27, this is typically around 7.75%. Interest is calculated daily from the due date until the date of payment.
What penalties apply for late Self Assessment?
Late filing: £100 immediately, then £10/day from 3 months (max £900), then £300 or 5% at 6 months, then £300 or 5% at 12 months. Late payment: 5% at 30 days, 5% at 6 months, 5% at 12 months.
Can I appeal HMRC penalties?
Yes, you can appeal if you have a 'reasonable excuse' such as serious illness, bereavement, HMRC errors, or events outside your control. You have 30 days from the penalty notice to appeal.
How is HMRC interest calculated?
Interest is calculated on a simple daily basis. The formula is: Tax owed × (Annual rate ÷ 365) × Number of days late. Interest is charged from the due date until payment is received.
When is Self Assessment tax due?
Self Assessment tax for the year ending 5 April is due by 31 January following the tax year. Payments on account (if applicable) are due 31 January and 31 July. Late payment interest starts the day after these deadlines.
31 January
Self Assessment deadline & 1st payment on account
31 July
2nd payment on account