Calculate late payment fees & generate a letter.

Find out how interest and compensation you're owed in less than a minute.

Then instantly generate a PDF letter to send to your debtor.

Late payments can put a serious strain on your cashflow. That’s why we’ve built a simple tool to help you calculate exactly how much compensation and statutory interest you can add to an overdue invoice under the Late Payment of Commercial Debts (Interest) Act 1998.

Once you’ve worked out what’s owed, you can download a ready-to-send PDF breakdown to attach to your chaser email or letter.

Image of Collect Compare mascot Tally using a computer

Late Payment Calculator and Letter Generator

Enter the invoice amount, due date and payment date, and our calculator will do the rest.


Enter the original invoice value before any interest or fees.


The date the invoice should have been paid by.


Leave as today’s date if the invoice is still unpaid.


If you have an invoice or PO reference, enter it here for clarity.


We’ll follow up in 7 days to see if payment was made.

What the calculator includes

Statutory interest

8% above the Bank of England base rate.

Fixed late payment fees

£40, £70 or £100 depending on invoice size.

Daily interest breakdown

see how the amount grows each day until the invoice is settled.