Late payment interest calculator
The work is done, the invoice is weeks old, and the silence is costing you sleep. This works out exactly what you can add for late payment, and writes the sentence to send. A specific number that grows every day gets invoices paid faster than any amount of polite nudging. Nothing you type is saved or sent anywhere.
Statutory interest applies when your client is a business. For homeowners and other consumers you can only charge interest if your quote or terms said you would.
30 days overdue
£1,584.79 now due
- Original invoice
- £1,500.00
- Interest at 12.0% a year
- £14.79
- Fixed compensation
- £70.00
- Growing daily by
- £0.49
Paste this into your reminder
This invoice for £1,500.00 is now 30 days past its due date. Under the Late Payment of Commercial Debts (Interest) Act 1998, statutory interest of £14.79 and compensation of £70.00 have been added, bringing the total due to £1,584.79. Please arrange payment at your earliest convenience.
SoloDesks chases unpaid invoices for you with one tap.
This is a general guide, not tax, legal or financial advice. Rates checked July 2026. Statutory interest applies to business-to-business debts, and the base rate changes over time. Always confirm the current rates and rules with HMRC or your accountant before relying on a figure.
Common questions
- Can I charge interest on a late invoice?
- If your client is a business, usually yes. In the UK the Late Payment of Commercial Debts (Interest) Act gives you the Bank of England base rate plus 8%, and a fixed compensation fee on top. The EU has a similar directive. If your client is a homeowner, you can only charge interest if your quote or terms said you would, which is a good reason to put a late payment line in your terms now.
- How much late payment interest can I add in the UK?
- Statutory interest is 8% plus the Bank of England base rate, calculated daily from the day after the due date. You can also add fixed compensation per invoice: 40 pounds for debts under 1,000, 70 pounds up to 10,000, and 100 pounds above that.
- Will charging interest ruin the relationship with my client?
- Mentioning it usually gets you paid without ever collecting it. The point of the calculation is the reminder message: a specific number, growing daily, moves your invoice to the top of their pile. Most tradespeople waive the interest the moment payment arrives.