Unpaid Invoice: What to Do When a Client Doesn't Pay (2025)

Step 1: Check before you chase

Before sending a reminder, make sure:

□The invoice was actually sent (check your outbox)
□The payment date has actually passed
□The invoice was addressed to the right person
□Your bank details / payment instructions are correct
□There isn't a dispute about the work quality that you haven't heard about

Step 2: The 4-stage escalation approach

Research shows that a structured escalation — where each email is slightly more urgent than the last — is the most effective way to recover unpaid invoices without damaging client relationships.

Stage 1: Friendly reminder (Day 3-5)

Subject: Re: Invoice INV-2025-042 — quick follow-up Hi [Name], I just wanted to follow up on invoice INV-2025-042 (£1,800) which was due on [date]. If you've already sent payment, please ignore this — thank you! Otherwise, I'd appreciate payment at your earliest convenience. Best, [Your Name]

💡 80% of late payments are resolved at this stage — clients simply forgot.

Stage 2: Firm follow-up (Day 7-10)

Subject: Invoice INV-2025-042 — payment overdue Hi [Name], I'm following up on invoice INV-2025-042 for £1,800, now [X] days overdue. Could you let me know when I can expect payment? If there's an issue with the invoice, I'm happy to discuss. Thank you, [Your Name]

💡 Ask directly: 'when can I expect payment?' Forces them to give a concrete answer.

Stage 3: Urgent notice (Day 14-21)

Subject: URGENT: Invoice INV-2025-042 — action required Hi [Name], Despite previous reminders, invoice INV-2025-042 for £1,800 remains unpaid at [X] days overdue. I need payment within 5 business days. I may need to pause any ongoing work and apply statutory late payment fees if this is not resolved. [Your Name]

💡 Mention potential consequences. Most clients pay before actual escalation.

Stage 4: Final demand (Day 30+)

Subject: Final demand: Invoice INV-2025-042 — £1,800 + statutory interest Dear [Name], This is a final demand for payment of invoice INV-2025-042 (£1,800), now [X] days overdue. Statutory interest of 8% per annum has accrued. If payment is not received within 14 days, I will take legal action without further notice. [Your Name]

💡 Formal language. Reference statutory interest. No more 'please' — this is a demand.

Your legal rights on unpaid invoices

Right	UK	EU (B2B)
Statutory interest	8% + Bank of England base rate (Late Payment Act 1998)	8% above ECB rate (Directive 2011/7/EU)
Fixed debt recovery costs	£40 for debts up to £999	€40 minimum
Late payment notice period	None required for B2B	30 days default, up to 60 by agreement
Small claims limit	Up to £10,000 (England & Wales)	Varies by country
Retention of title	Yes, if stated in contract	Yes, if stated in contract

When to escalate to legal action

If Stage 4 doesn't work, you have options:

Small claims court (UK)

💰 Cost: £35–£455 fee⏱ Time: 2–6 months✓ Amounts up to £10,000, clear-cut cases✗ Time-consuming, no guarantee of collection

Debt collection agency

💰 Cost: 10–25% of recovered amount⏱ Time: Variable✓ No upfront cost, professionals handle it✗ Damages client relationship permanently

Solicitor's letter before action

💰 Cost: £100–£300⏱ Time: 1–2 weeks✓ High success rate, professional leverage✗ Cost may exceed value for small invoices

Statutory demand

💰 Cost: Free to file⏱ Time: 21 days notice✓ Serious pressure on companies✗ Only viable for debts over £750 in UK

How to prevent unpaid invoices in the future

Get a signed contract before starting

Define scope, payment terms, and late payment fees in writing. This protects you legally and sets expectations.

Take a deposit upfront

50% before you start for new clients. Screens out bad-faith clients and gives you leverage to stop work if payment fails.

Invoice immediately on delivery

Don't wait. Every day you delay extending the client's 'free money' window.

Use Net 14 instead of Net 30

Clients who need Net 30 can ask — but starting at Net 14 means you get paid sooner on average.

Send automated reminders

Set up automatic payment reminders (Chaser does this) so you never forget to follow up.

Add late payment fees to your contract

Clients are less likely to pay late when there's a financial consequence.

🐕 Automate the whole process with Chaser

Chaser watches your invoices and automatically sends Stages 1–4 at the right intervals. You set it and forget it. Most users recover 40% more unpaid invoices within the first month.

✓Automatic 4-stage email escalation
✓See when clients open your emails
✓One-click mark paid
✓Free for up to 3 invoices

Try Chaser free →

FAQs about unpaid invoices

After how long is an unpaid invoice considered a bad debt?

There's no fixed legal timeline, but HMRC allows you to write off a bad debt for VAT purposes after 6 months. For income tax, you can write off when it becomes clearly uncollectable.

Can I charge interest on an unpaid invoice?

Yes. UK law (Late Payment of Commercial Debts Act 1998) gives you the right to charge 8% + Bank of England base rate per year on B2B invoices, automatically — no need to state it in your contract.

What if my client disputes the invoice?

Respond in writing, outline what was agreed, and offer to discuss. If you have a signed contract or scope-of-work document, you're in a strong position. For amounts over £500, consider formal mediation.

Can I take an unpaid invoice to court without a lawyer?

Yes — the UK small claims court (Money Claim Online, up to £10,000) is designed to be used without legal representation. Filing fees start at £35.

Should I send a letter before action by email or post?

Email is fine for most cases and creates a clear timestamp. For large amounts or unresponsive clients, send both email AND recorded post for the strongest evidence trail.