Late payment calculator

Late Payment calculator (unpaid commercial debts and invoices).

Use our free calculator below to work out the amount of interest and compensation that can be claimed for any unpaid business debts / invoices. If you are intending to take legal action to reclaim the money, the calculator also provides you with suitable wording for your claim. The calculator has been updated to include interest rates up to January 2021.

Late Payment Calculator

Date invoice became due:

Amount unpaid (£):

Date invoice was paid(if not paid yet, use today):


To use the calculator you will need to know the date on which the payment was due, date paid (if debt has been paid) and the amount of the debt.

Date due: The date by which the debt should have been paid. Typically this might be 30 days after the invoice date.

Amount of debt: This is the amount of the debt that is still outstanding (or was paid late).

Date paid: The date on which the debt was paid, or if still outstanding use the current date.