Freelance Money Tools
Invoicing

The invoice is 30 days late. Here's what that costs them.

Late fees aren't about the money — they're about making “pay the freelancer” move up the client's to-do list. Calculate the fee and the new balance.

Standard 1.5%/month convention
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Tax data last updated: July 2026. Sources & methodology

The overdue invoice

$
days
%

1.5%/month (18%/yr) is the common ceiling; some states cap lower.

Late fee owed
$38

1.5% per month, prorated across 30 days.

Original invoice
$2,500
Late fee
$38
New balance due
$2,538

A late fee is only enforceable if it was in the contract or invoice terms the client agreed to beforethe work — you can't bolt it on after. Some US states cap interest on overdue commercial invoices; check yours before charging above 1.5%/month.

How this is calculated

The percent-per-month method is the commercial standard: the fee is your monthly rate applied to the invoice amount, prorated by days overdue. At the common 1.5% per month, a $2,500 invoice thirty days late accrues $37.50 — small on purpose. It's a nudge with paperwork behind it, not a revenue stream.

The flat-fee alternative charges one fixed amount regardless of delay. It's simpler to state on an invoice but does nothing extra as the delay stretches, which is exactly when you want pressure to build — most freelancers who've dealt with chronic late payers end up preferring the monthly percentage.

Formula
Fee = invoice × monthly rate × (days late ÷ 30)

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Common questions

Not enforceably. The fee has to be in terms the client agreed to before the work — contract, signed proposal, or invoice terms they accepted. What you can do today: add the clause to every future contract, and send this one a firm reminder instead.
It's within bounds in most US states for commercial invoices, but a few cap interest lower, and consumer clients have stricter rules than business clients. If you plan to charge more than 1.5%, spend ten minutes on your state's usury limits first.
Often they get waived — strategically. “I'll waive the $75 late fee if payment arrives this week” turns the fee into leverage, which was its real job. Clients who see fees accruing also tend to pay the next invoice on time, which is the outcome you wanted.
Day 1 overdue: friendly nudge, assume it slipped through. Week 2: firmer note mentioning the late fee is accruing. Week 4: pause any ongoing work — that clause should be in your contract too. Beyond that: small claims court or collections, depending on the amount.