My client is 45 days late on an invoice. What do I send now?

First, check your paperwork

Before you write, gather three things:

1. The agreement. What it says about payment terms, late fees and who approves invoices. If you only have emails, collect the ones where the price and deliverables were agreed.
2. The invoice. Confirm it went to the right person with the right purchase order or reference. A surprising share of late invoices are stuck because they went to the wrong inbox.
3. Proof of delivery. The date you delivered the final files and any message accepting them.

The message to send now

Subject: Invoice [number], now 45 days overdue

Hi [name], I'm following up on invoice [number] for [amount], issued on [date] and due on [date]. I haven't received payment or a reply to my earlier reminder. Could you confirm today when it will be paid? Payment details are on the invoice, which I've attached again. If there's a problem with the invoice, let me know and I'll fix it straight away.

Keep it factual. No apologies, no anger, and no new threats you are not ready to carry out. Copy the person who signed the agreement if your contact has gone quiet.

Late fees and interest

You can only add a late fee that your agreement allows, or that the law where you work provides. Two examples show how much this varies.

In the UK, the government guidance on late commercial payments says that if no payment date was agreed, payment is late 30 days after the customer gets the invoice or you deliver the service, whichever is later, and agreed dates must usually be within 60 days for business transactions. Its page on interest on late commercial payments sets statutory interest at 8 percent plus the Bank of England base rate for business to business transactions, unless the contract sets a different rate, and tells you to send a new invoice if you add it.

In New York State, the Department of Labor page on the Freelance Isn't Free Act explains that from August 28, 2024, Article 44-A of the General Business Law gives freelancers contract requirements and a formal enforcement process, with complaints going to the State Attorney General. The Department's model freelance worker agreement covers work worth $800 or more, alone or added up across contracts with the same hiring party over the previous 120 days, offers a default of payment no later than 30 days after the work is complete, and includes a blank late fee percentage per month.

Other states and countries have different rules or none. Look up yours before you quote a law in an email. This is not legal advice, check with a lawyer where you work before you threaten action.

A timeline from here

When	What to send
Today	The follow-up above, invoice attached
About a week later, no reply	A final notice: amount, any late fee your contract allows, a firm date, and what happens next
After the final notice date	Stop new work for the client, and decide whether to use a small claims court, a state process, or a collections route

Stopping work matters. If you are still delivering on another project for the same client, a pause until the overdue invoice is paid is often the most effective step you have, provided your agreement allows it.

Preventing the next one

Most of the leverage is set before the project starts: a deposit, staged payments, clear terms and a written kill fee clause. The thread on what a fair kill fee is covers that clause, and the thread on working out a minimum hourly rate explains why late payers belong in your rate as a cost. For payment terms you can copy into your next proposal, see freelance designer rates and contracts.