What should you actually charge, and say, about a late invoice?
Work out a fair late fee, then generate a ready-to-send reminder message matched to how overdue the invoice actually is.
Matched automatically to how overdue this invoice is, friendly for a few days late, firmer the longer it goes unpaid.
Setting this up before an invoice is ever late
A late fee only holds up if it was disclosed upfront, ideally in writing on the original invoice or contract, before the work started. Adding one retroactively to an invoice that never mentioned it is a much harder conversation, and not one most clients will accept gracefully.
For the full staged approach to following up on a late invoice without damaging the relationship, see the chasing late invoices guide.
About this calculator
What is a reasonable late fee for a freelance invoice?
One to one and a half percent per month on the outstanding balance is the common range, equivalent to roughly 12 to 18 percent annually. A flat fee works for smaller invoices where a percentage would be trivial. Enforceable limits vary by jurisdiction, so check what applies where you are.
Can I charge a late fee if it was not in the contract?
It is much weaker ground. A late fee works because both parties agreed to it in advance, which is why it belongs in your standard terms from the start even though you will rarely charge one. Its real function is to make the due date feel concrete. See the contracts guide.
Should I actually charge a client a late fee?
Often the more useful move is to reference it rather than apply it: "a late fee of X applies after Y days, which I would rather not add" prompts payment while leaving the relationship intact. Apply it when an invoice is substantially overdue and previous messages have gone unanswered. The late invoice guide sets out the full escalation.
Know the rate behind the number
Every calculation here starts from what you charge. If you have never worked out what that should be, the rate calculator does it from your real costs.
Work out my true rate