What to Do When a Client Won’t Pay Your Invoice

Step 1: Re-read the contract before you chase

Before you write the first reminder, find the payment clause. Your leverage comes from what the contract actually says, and four things decide it:

Whatever you find, the response is the same: chase in writing, cite the contract, and escalate in steps. An angry phone call creates nothing you can point to later.

• Is there a hard due date? "Payment upon receipt" or "within a reasonable time" sets no deadline — with nothing to breach, there is nothing to enforce.
• Is there a late fee? If the contract says nothing about late payment, waiting costs the client nothing.
• Can they withhold over any dispute? Language like "withhold or offset any amounts" turns a minor complaint into a license not to pay the whole invoice.
• Where would you have to sue? Mandatory arbitration or the client’s home state as venue can make enforcing a small invoice cost more than the invoice.

Step 2: Send a reminder that cites the contract

A good reminder is short, polite, and specific: the invoice number, the amount, the due date, and the exact contract wording that makes it due. If the contract has a 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 it a deadline: "if we don’t receive payment by [date], we’ll send a formal demand." That sentence is what turns a nudge into the first step of an escalation — and it puts the client on notice in writing.

Step 3: Escalate to a formal demand letter

When the reminder deadline passes, the next message gets more formal while the tone stays calm. A formal demand letter states the amount owed, the contract basis for the debt, a deadline for payment, and what happens next if the deadline passes. Conservative wording is the point: the letter’s job is to be accurate and professional, because it may end up in front of a judge.

The three stages — friendly reminder, formal demand, final notice — work as a sequence, not a menu. Each one documents that the client was told, in writing, what they owed and what would happen next. By the final notice, the paper trail does most of the talking.

Step 4: Decide whether small claims is worth it

Small claims court is the venue designed for exactly this kind of dispute — but only if your contract does not force you into arbitration or a distant forum. Before filing, check the venue and arbitration clauses: a clause that sends every dispute to the client’s home state multiplies the cost of enforcing a small invoice, often beyond the invoice value. That is what makes a winnable case economically impossible.

If venue is clean, file where the contract allows, and bring the contract, the invoice, and the written record from steps 2 and 3. The escalation trail you built is most of the case.

Step 5: Fix the contract before the next client

Getting stiffed once is the market. Getting stiffed twice is the contract. Before the next engagement, put the five protections in writing:

You don’t have to draft these from scratch — the same wording our review engine flags as missing is already built into the free templates in the document center, and the scanner will tell you in 60 seconds which of the five your next contract lacks.

• A hard payment window — "net 14 from invoice date." Anything in the net 14 to net 30 range works; what matters is that a number exists.
• A late fee — 1.5% per month, or the maximum your state permits, whichever is lower.
• A deemed-acceptance window — no written objection within 7 days of delivery means accepted.
• A withholding cap — only the itemized portion of a written dispute can be held back.
• A small-claims carve-out — disputes under a stated amount stay in your local small claims court.

The clauses behind this playbook