Late Fee on an Overdue Invoice: How Much to Charge and How to Ask
A late fee is the contract’s price for paying late: overdue balances accrue a monthly charge, typically 1.5% per month (18% APR) or the maximum rate your state permits, whichever is lower. The fee only sticks if the contract says so before the invoice goes out. Without a clause, charging one is much harder — you fall back on statutory interest, which is often small.
What a late fee is (and why it lives in the contract)
A late fee is the contractual price of paying after the due date: overdue balances accrue a monthly charge until they are paid. The rate, the start date, and your right to collect all come from the contract. The invoice can restate the terms, but the contract is what binds.
The clause matters because of cost. A contract that sets a payment date and says nothing about lateness lets the client wait 90 days at zero cost, and small-claims escalation becomes your only tool. A stated late fee is what turns delay from free into expensive.
How much late fee to charge: 1.5% per month is the standard ask
1.5% per month works out to 18% APR, and it pairs with a hard payment window such as net 14 from invoice date. Keep the number modest: a rate that runs past your state’s usury limit risks making the clause unenforceable, which loses you the fee and the deadline in one sentence.
The formulation that travels across states caps itself: 1.5% per month, or the maximum rate permitted by applicable state law, whichever is lower. The lower number always applies, so the clause never asks for more than the state allows.
The wording to put in the contract
One sentence carries the protection: "Overdue balances accrue a late charge of 1.5% per month (18% APR), or the maximum rate permitted by applicable state law, whichever is lower."
A late fee needs a deadline to attach to. Pair it with a hard payment window — "Client shall pay the full invoice within 14 calendar days of receipt" — and overdue has a definition. With "payment upon receipt" there is no breach to point to, which leaves the late fee with nothing to be late about.
How to charge it when an invoice runs late
When the due date passes, send a reminder that cites the contract: the invoice number, the amount, the due date, and the exact payment wording that makes it due. If the contract has the late-fee clause, mention it once — state the rate and when it starts accruing, then stop. A reminder that reads like a threat costs you the professional high ground; a reminder that cites the contract gives the client a reason to pay that their accountant understands.
Give the reminder a deadline: if payment does not arrive by a stated date, the next message is a formal demand. The sequence — friendly reminder, formal demand, final notice — documents that the client was told, in writing, what they owed and what would happen next.
No late-fee clause in the contract? Where you stand
Charging a late fee without a contractual rate is generally much harder: there is no agreed number to point to, and you fall back on statutory interest, which is often small. The clause is the tool.
What still works is the written record: the reminders, the formal demand letter, the invoice, and the escalation sequence. Work the collection playbook in order, and fix the contract before the next engagement — a hard payment window, the late-fee sentence, and a withholding cap so a minor complaint cannot freeze the whole invoice.
Questions freelancers ask
Is 1.5% per month a legal late fee?
It equals 18% APR, and state usury limits vary. The standard safe formulation is the lower of the two: 1.5% per month, or the maximum rate permitted by applicable state law. That keeps the clause enforceable across states instead of betting on one state’s cap.
Can I add a late fee to an invoice if the contract is silent?
Generally much harder. Without a contractual rate there is no agreed number to point to, and you fall back on statutory interest, which is often small. The next contract should carry the clause; this invoice moves on reminders and a formal demand.
When does a late fee start accruing?
When the balance becomes overdue, which means the contract first needs a hard due date such as "net 14 from invoice date." Terms like "payment upon receipt" set no deadline, so there is no breach to point to and nothing for the fee to attach to.
Late fee or interest — which term should the contract use?
In freelance contracts the late charge is written as a monthly rate, so the two labels describe the same number. What matters is the amount, the whichever-is-lower cap, and that the wording sits in the contract rather than only on the invoice.
The clauses behind this playbook
Chasing an unpaid invoice right now?
The free 3-stage generator writes the reminder, the formal demand, and the final notice — conservative wording, state-safe.
Write a demand letter free →Before the next contract
Paste the client's contract into the scanner. In 60 seconds you'll see which payment protections are missing. First scan free.
Scan a contract free →Educational content only — not legal advice, and it creates no attorney–client relationship. Every step maps to the same public legal resources our contract reviews cite. For anything material to you, consult a licensed attorney in your state.