How to Charge Late Fees on Invoices

How to add a late payment fee to your invoices, how much to charge, the wording to use, and how to enforce it without losing the client.

By the Invoiceflint team · Updated October 31, 2026

A late fee gives clients a reason to pay on time and compensates you when they don't. Used well, it's rarely charged — its main job is to move your invoice up the client's priority list.

Agree on it before the work starts

A late fee that appears for the first time on an overdue invoice feels like a penalty sprung on the client, and may not be enforceable. Put your late fee policy in your estimate or contract, then repeat it on every invoice.

Common late fee structures

Type	Example	Notes
Flat fee	$25 if payment is more than 15 days late	Simple and easy to explain
Monthly percentage	1.5% per month on the overdue balance	Common with business clients
One-time percentage	5% of the invoice total once overdue	Scales with the size of the job

Check the legal limits

Rules on late fees and interest vary by country and state, and often differ for consumers and businesses. In the UK and the EU, businesses have a statutory right to claim interest on late payments from other businesses. In the US, limits are set state by state. If you're unsure, check with a local accountant or lawyer before setting your rate.

Example wording

On your estimate and invoices

Payment is due within 14 days of the invoice date. Balances unpaid after 30 days incur a late fee of 1.5% per month.

Should you actually charge it?

Use judgment. Waiving the fee once for a good client who apologizes builds goodwill; enforcing it consistently for clients who are always late protects your cash flow. What matters most is that the policy is clear, so the conversation is about the agreed terms rather than your feelings.

Invoiceflint flags overdue invoices automatically, and Invoiceflint Pro can send email reminders before and after the due date, so most invoices get paid before a late fee ever comes up.