You can usually charge a late fee on an unpaid invoice if your client agreed to it before the work began and the invoice states it. Most businesses charge either a flat fee or a monthly percentage of the overdue balance.
A late fee isn't really about the money. It's a clear signal that your due dates are real. Here's how to set one up so it's fair, enforceable, and rarely needed.
When you can charge a late fee
- It was agreed in advance. Put the late fee in your proposal, contract, or written terms before you start the work.
- It's on the invoice. Repeat the policy on every invoice, next to the due date.
- It's reasonable. A fee that's out of proportion to the debt is more likely to be challenged.
- It follows local rules. Some countries and US states limit late fees or interest on overdue payments. Check what applies to you.
Flat vs percentage late fees
| Type | How it works | Example |
|---|---|---|
| Flat fee, once | A fixed amount added once the invoice is late. | $35 added to a $1,200 invoice |
| Percentage, once | A percentage of the balance, added once. | 2% of $2,000 = $40 |
| Percentage, monthly | A percentage of the unpaid balance for each month it stays late. | 1.5% of $2,000 = $30 per month |
| Flat fee, recurring | A fixed amount for each week or month it stays late. | $25 per month until paid |
Flat fees are simple and feel fair on small invoices. Percentages scale with the size of the invoice, which suits larger projects.
Late fee wording you can use
For your contract or terms:
For the invoice itself:
For a reminder once the fee applies:
For more reminder wording, see our payment reminder email templates.
Tips for using late fees well
- Make paying on time easy. A pay-online link does more to prevent late payment than any fee.
- Remind before you charge. A friendly reminder on the due date catches most forgotten invoices.
- Be consistent. A policy you apply sometimes is hard to apply at all.
- Use discretion. Waiving a first late fee for a good client can earn more goodwill than the fee is worth.
How Clientary helps
Clientary can add a late fee to any invoice, as a flat amount or a percentage, charged once or every day, week, or month it stays unpaid, with tax applied when the invoice is taxed. Pair it with automatic payment reminders and most invoices get paid before a fee is ever needed.
This guide is general information, not legal advice.
