Calculate exactly what you're owed under the Late Payment of Commercial Debts Act 1998. Includes statutory interest at 11.75% and fixed compensation.
Under the Late Payment of Commercial Debts (Interest) Act 1998, all UK businesses have the automatic right to charge interest on overdue invoices. You don't need to have included this in your contract — it applies by default to every business-to-business transaction.
The statutory interest rate is 8% per year above the Bank of England base rate. With the current base rate at 3.75%, that gives a total rate of 11.75%. Interest is calculated daily from the date the payment was originally due.
On top of interest, you can claim a fixed sum for debt recovery costs. The amount depends on the size of the debt:
The UK government is tightening rules around late payment. From 2026, large companies that consistently pay late can be removed from the Prompt Payment Code and barred from public sector contracts. Finance directors will be personally accountable for payment reporting, and the Small Business Commissioner is gaining new enforcement powers.
Knowing the maths is one thing. Actually getting paid is another. The most effective approach is a structured escalation: polite reminder on day 1, firmer follow-up at day 7, formal notice with interest calculations at day 14, letter before action at day 21, and County Court claim via Money Claim Online if all else fails. Most clients pay when they see you know the process.
Even better — prevent the problem entirely with signed digital contracts, automated payment reminders, and a system that handles the escalation for you.
Certi automates the entire invoice escalation process — from polite reminders to statutory interest calculations — so you get paid without the stress.
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