Question 1

What is a normal late fee on an invoice?

Accepted Answer

The most common late fee for freelancers and small businesses in the US is 1.5% per month (18% APR). Some businesses use a flat fee — typically $25 to $50 — instead of a percentage. Whatever you choose, the rate has to be in your contract before the work starts.

Question 2

Is it legal to charge a late fee?

Accepted Answer

In most jurisdictions, yes — but only if the client agreed to it before you delivered the work. In the US, late fee caps are set at the state level (anywhere from 5% to 18% APR is typical). The UK, EU, and Canada have their own statutory late payment rules. This calculator gives you the math; check your local cap before invoicing.

Question 3

How do I calculate a 1.5% monthly late fee?

Accepted Answer

Multiply the unpaid balance by 1.5% (0.015), then prorate by the number of days overdue divided by 30. On a $1,000 invoice that is 24 days late, that's $1,000 × 0.015 × (24 / 30) = $12.00. The calculator does this automatically and shows the line to paste into the invoice.

Question 4

When should I add the late fee — at 1 day overdue or after a grace period?

Accepted Answer

Most freelancers wait through a 5–10 day grace period before adding the fee. That gives the client's accounts payable team breathing room and keeps you from charging over a one-day banking delay. Set the grace period in the calculator and only the days outside it will be charged.

Question 5

Should I use a daily rate or a monthly rate?

Accepted Answer

Monthly (1.5%) is the most common and the easiest to defend. Daily rates (e.g., 0.05% per day) are more aggressive and work well for shorter contracts where even a week matters. Annual (APR) framing — 18% per year, for example — is the same math but reads as more formal.

Question 6

Can I add a late fee retroactively if it wasn't in my contract?

Accepted Answer

No. Late fees only stick if the client agreed to them in the original contract or signed quote. If your current contract doesn't mention a late payment penalty, you can still send a polite reminder, but the fee itself isn't enforceable. Add a clear late fee clause to every future contract.

Question 7

How do I word a late fee on an invoice?

Accepted Answer

Keep it short and reference the contract: "Late payment fee (1.5% per month, 24 days overdue): $12.00. Per Section 4 of our agreement." The copy-ready line in this calculator follows that pattern — clear, dated, and traceable back to the contract.

Question 8

Does this calculator work for international invoices?

Accepted Answer

Yes. Pick the currency (USD, EUR, GBP, CAD, AUD, JPY, or CNY) and the calculator formats the result correctly. The math is the same; just confirm the late fee cap in the client's country before you invoice.

Late Fee Calculator

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