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Free UK Late Payment
Interest Calculator

Work out exactly what you're legally owed on an overdue invoice — statutory interest plus compensation, calculated instantly under UK law. Nothing you enter is ever stored.

Enter the details

£
%
Current rate as of Aug 2026 — pre-filled, but check bankofengland.co.uk if it's since changed.
Total now owed
£1,000.00
0 days overdue
Original amount£1,000.00
Statutory interest (11.75% p.a.)£0.00
Statutory compensation£40.00
Total owed£1,000.00

How this is calculated

Under the Late Payment of Commercial Debts (Interest) Act 1998, UK businesses are automatically entitled to charge statutory interest on overdue B2B invoices — you don't need it written into your contract. The rate is the Bank of England base rate plus 8%, applied daily from the day after the payment was due.

On top of interest, you're also entitled to a fixed compensation fee for the cost of chasing payment: £40 for debts under £1,000, £70 for £1,000–£10,000, and £100 for anything larger.

This calculator covers commercial (B2B) debts under UK law and is provided for convenience, not legal advice — consumer debts follow different rules, and if a payment dispute is heading anywhere formal, a professional's guidance is worth getting.

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Practical money guidance

Late Payment Calculator Guide

Late-payment interest depends on what kind of debt you are dealing with and the terms that apply. For UK commercial debts, statutory interest can apply to qualifying business-to-business transactions, but a contractual rate may change the position.

How to use the result sensibly

  1. Identify the unpaid amount and the date the payment became overdue.
  2. Check whether the debt is a qualifying commercial transaction and whether your contract specifies a different interest rate.
  3. For statutory commercial interest, verify the applicable Bank of England reference rate for the relevant period rather than assuming today's rate automatically applies.

Quick example

The general statutory commercial-interest formula is annual interest = debt × statutory annual rate, then daily interest = annual interest ÷ 365. The total interest depends on the number of overdue days. Use the calculator as an estimate and verify the applicable rate and dates before issuing a demand.

Common questions

What is statutory interest on a late commercial payment?

GOV.UK states that qualifying business-to-business late payments can carry statutory interest at 8 percentage points above the relevant Bank of England base rate, unless a different contractual rate applies.

When is a business payment late?

Where no payment date has been agreed, GOV.UK sets out a statutory timetable that commonly uses 30 days from receiving the invoice or delivery of the goods or service, whichever is later. Agreed terms can change the due date.

Can I simply use the current Bank Rate?

Not necessarily. The statutory commercial-payment regime uses reference dates for the Bank of England rate. Check the official guidance for the period in which the debt became late.

UsefulFox calculations are for general information and planning. Check current official guidance, contractual terms and professional advice where the result affects tax, legal rights or a financial decision.