Free Invoice Generator

Late payment fee calculator

Work out what an overdue invoice is worth now: the balance, plus the late fee your terms allow. Choose a one-off percentage, a flat amount, or a monthly charge.

The unpaid invoice

What is still unpaid, before any late fee.

Used only if you press Create this invoice, as the name of the balance line.

How overdue it is

The day it was due, not the day it was issued. The due date calculator works that out from your terms.

Today, or the day you expect to be paid.

Days after the due date before a fee starts. Leave at 0 if your terms have none.

The fee your terms allow

Charged once, however long the invoice stays unpaid.

The rate is yours to set. What you may charge, and whether it is enforceable at all, depends on where you are and on what the contract said before the work started.

GuideLate payment feesHow this works, and where the figures go wrong →

What the late payment fee calculator does not do

  • It doesn't know what you're allowed to charge. Late fee caps, statutory interest and whether a fee is enforceable without a written term depend on your country, and often on the state or province. Check the rules where you are, or ask a professional adviser. I recommend putting the rate in the contract before the work starts.
  • It doesn't compound, and it doesn't add tax to the fee. Whether a late fee is taxable depends on where you are. In some places it is; in others it falls outside the scope of the tax.
  • It counts calendar days. Public holidays and working days don't come into it, because late payment terms are normally written in calendar days.
  • It doesn't keep anything. Nothing is written to your browser's storage while you use it and nothing is sent to us, so the figures are gone when you close the tab. Press Create this invoice if you need a document: the balance and the fee are handed to the invoice generator in this tab as two lines, and cleared as soon as it opens.

Related

For interest that runs daily on the balance, rather than a charge applied once, use the late payment interest calculator. It's a different charge, though it often gets called a late fee. To work out the due date this page needs, the invoice due date calculator takes the invoice date and your terms. For the invoice itself rather than what it has cost you to chase, the invoice calculator takes line items, a discount and a deposit. If the fee goes unpaid along with the invoice, the final notice letter generator puts it into the last letter before you hand the debt on.

Last updated 20 September 2026