Guide7 min read

How to Follow Up on an Unpaid Invoice

Most late payments aren't deliberate — they slip through because clients are busy, invoices get buried, or payment processes are slow. A structured follow-up sequence gets most overdue invoices paid without damaging the relationship. Here's exactly how to do it.

The 5-step follow-up sequence

StepWhen to sendTone
1. Due date reminderSame day invoice is dueFriendly, neutral
2. First follow-up7 days overduePolite, matter-of-fact
3. Second follow-up14 days overdueDirect, asking for response
4. Formal notice30 days overdueFirm, clear deadline
5. Final notice45+ days overdueFinal, mentions consequences

The 80% rule

About 80% of late payments are resolved at step 1 or 2 — the client simply forgot. Keep your first two reminders short and non-accusatory. Save the formal tone for step 4+.

Copy-paste email templates

Reminder #1 — Due today

Send on the due date

Subject:

Invoice INV-042 due today — [Your Name]

Body:

Hi [Client name],

Just a quick note that Invoice INV-042 for $[amount] is due today.

You can view and download the invoice here: [invoice link]

If you've already sent payment, please ignore this — and let me know the reference number so I can confirm receipt.

Thanks,
[Your name]

Reminder #2 — 7 days overdue

Send 7 days after due date

Subject:

Invoice INV-042 — 7 days overdue

Body:

Hi [Client name],

I wanted to follow up on Invoice INV-042 for $[amount], which was due on [due date] and is now 7 days overdue.

Could you let me know when I can expect payment, or flag if there's any issue on your end?

Invoice link: [invoice link]

Thanks,
[Your name]

Reminder #3 — 14 days overdue

Send 14 days after due date

Subject:

Second notice: Invoice INV-042 overdue

Body:

Hi [Client name],

Invoice INV-042 for $[amount] is now 14 days past due. I've sent two previous reminders and haven't received payment or a response.

Could you please confirm your expected payment date? If there's a dispute or an issue with the invoice, let me know and I'm happy to discuss it.

Invoice: [invoice link]

[Your name]

Reminder #4 — 30 days overdue

Send 30 days after due date — escalate

Subject:

Invoice INV-042 — 30 days overdue, please respond

Body:

Hi [Client name],

Invoice INV-042 for $[amount] is now 30 days past the due date. I've reached out several times without response.

Please reply by [date 7 days from now] with either payment confirmation or a clear timeline for payment. If I don't hear back, I'll need to consider formal options for recovering this debt.

I'd prefer to resolve this directly — please get in touch.

[Your name]

Final notice — 45+ days overdue

Send 45+ days after due date

Subject:

Final notice — Invoice INV-042

Body:

Dear [Client name],

This is a final notice regarding Invoice INV-042 for $[amount], which has been outstanding for [X] days.

If I do not receive payment or a confirmed payment arrangement by [specific date], I will pursue recovery through [small claims court / a debt collection agency / legal action].

Payment can be made via [payment details] or by replying to arrange an alternative.

[Your name]

What to do if they still don't pay

If you've completed the 5-step sequence and still haven't received payment or a response, you have several options:

Small claims court

US: up to $10,000–$25,000 depending on state. UK: up to £10,000 through Money Claim Online (MCOL). Filing costs £35–£455 in the UK, typically $30–$100 in the US. Fast and doesn't require a lawyer.

Debt collection agency

They take a percentage (typically 20–40%) of the recovered amount. Best for debts you've given up on recovering yourself. It's not worth using for small amounts.

Statutory demand (UK)

For debts over £750 owed by a company. A formal legal notice that can lead to winding-up proceedings if unpaid within 21 days. Powerful but expensive — consult a solicitor.

Invoice factoring

Sell your overdue invoice to a factoring company at a discount (typically 80–90% of face value) in exchange for immediate cash. Useful for large invoices from otherwise creditworthy clients.

How to prevent late payments in the first place

Require a deposit before starting work

30–50% upfront means you're never chasing 100% of an invoice. Clients who pay deposits are serious clients.

Use shorter payment terms

Net 30 is the default but Net 14 or Net 7 is fine — most clients will accept it. Fewer days = less time for invoices to get buried.

Send invoices immediately on completion

Don't batch invoices or wait until month-end. The sooner you invoice, the sooner the payment clock starts.

Send a shareable link, not just a PDF attachment

A link in the email is harder to lose than an attachment. SwiftBill generates a public link for every invoice automatically.

Add a late fee clause to your contracts

'Invoices unpaid after 14 days will incur a 2% monthly late fee.' Even if you never enforce it, it signals you take payment seriously.

Tone guide: how formal to be at each stage

The biggest mistake freelancers make is going straight to aggressive language on the first reminder. Here's how to calibrate:

  • Steps 1–2: Treat it like a friendly admin task, not a confrontation. Most clients are just busy.
  • Step 3: Shift from friendly to businesslike. Ask directly for a response or payment date.
  • Step 4: Set a clear deadline. “Please respond by [date]” — not open-ended.
  • Step 5: State consequences clearly but without anger. “I will pursue this through small claims court” — not “I'm going to destroy you.”

Track which invoices are paid — free

SwiftBill tracks payment status for every invoice. Know exactly what's overdue without digging through email.