How long should I wait before chasing an unpaid invoice?

Follow up on Day 1 overdue — not a week later. Most late payments are simply oversights, and a prompt reminder resolves them quickly. Waiting signals that your due date is flexible.

How do I chase a payment without damaging the client relationship?

Lead with curiosity, not accusation. "I wanted to check if there's anything I can do to help process this" is less confrontational than "You haven't paid." Keep the focus on solving the problem, not assigning blame. Most clients appreciate professionalism even when being chased.

Can I charge late fees on an overdue invoice?

Yes, if your payment terms include a late fee clause and those terms were agreed before the work started (in a contract or on a previously accepted invoice). In the EU, statutory interest applies automatically under the Late Payment Directive — even without a clause.

What if the client disputes the invoice?

Ask them to send the specific dispute in writing within 24–48 hours. Legitimate disputes should be resolved quickly; vague or last-minute objections after the due date are often a stalling tactic. Resolve genuine issues fast and expect payment for the undisputed amount in the meantime.

Can I add interest to an overdue invoice without a contract clause?

In the UK and EU, yes. The Late Payment of Commercial Debts (Interest) Act 1998 (UK) and Directive 2011/7/EU (EU) both give you a statutory right to charge interest on overdue B2B invoices automatically — no contract clause or prior agreement needed. In the UK the rate is 8% above the BoE base rate; in the EU it is the ECB reference rate plus 8 percentage points. EU creditors can also claim a flat €40 recovery fee per invoice. Outside these jurisdictions, you generally need a clause in your contract or accepted terms of service.

What's the difference between a payment reminder and a debt collection letter?

A payment reminder assumes good faith — it's a short, professional nudge that the invoice is overdue, sent before you know whether the delay is deliberate. A debt collection letter (or formal demand) is a legal document asserting the debt, specifying a final deadline, and warning of specific consequences (court claim, statutory demand, or agency referral). Tone, format, and legal weight are different. Use reminders first; move to a formal demand only after two or three ignored reminders at the 14–30 day mark.

Chase an Unpaid Invoice: Email Scripts & Templates

More than half of B2B invoices are paid after the due date. For most of them the reason is mundane: the invoice got buried, forwarded to the wrong person, or forgotten. Knowing how to follow up professionally — without damaging the client relationship — is a core business skill.

What is chasing an unpaid invoice? Chasing an unpaid invoice means sending structured follow-up messages — by email, phone, or formal letter — to a client whose payment is overdue. A prompt, professional sequence resolves the vast majority of late invoices before escalation is needed, because most delays are administrative rather than deliberate.

This guide gives you a complete system: a timeline, email templates, phone scripts, and escalation options for when polite reminders don't work.

Follow Up Immediately — Every Day You Wait Costs You

Every day you delay chasing signals to the client that your due date is flexible. It isn't — so don't act like it is.

Chasing Timeline

3–5 Days Before the Due Date: Friendly Reminder

A proactive nudge before the deadline prevents the awkward overdue conversation entirely.

Subject: Friendly reminder — Invoice #[INV-001] due [date]

Hi [Name],

Just a quick note to flag that Invoice #[INV-001] for [amount] is due on [date]. Please let me know if you need anything from me to process it — happy to resend in a different format if helpful.

Thanks,
[Your name]

Day 1 Overdue: Polite Follow-Up

Contact on the first business day past the due date. Keep it short and assume good intent — it's likely an oversight.

Subject: Invoice #[INV-001] — payment due [date]

Hi [Name],

I noticed that Invoice #[INV-001] for [amount] was due on [date] and doesn't appear to have been processed yet. Could you let me know when I can expect payment, or flag any issues with the invoice?

I've attached a copy for reference.

Best,
[Your name]

Day 7 Overdue: Firmer Follow-Up

If no response or payment after a week, escalate the tone slightly. Mention your late fee policy if you have one.

Subject: Invoice #[INV-001] — 7 days overdue

Hi [Name],

Invoice #[INV-001] for [amount] is now 7 days past its due date of [date]. I'd appreciate payment or a response confirming when to expect it.

As a reminder, our payment terms include a late fee of [X]% per month on outstanding balances. I'd prefer to resolve this without applying the fee — please get back to me today if possible.

Regards,
[Your name]

Day 14 Overdue: Final Warning Before Escalation

Two weeks overdue with no contact warrants a clear escalation warning.

Subject: Invoice #[INV-001] — FINAL NOTICE before escalation

Hi [Name],

Invoice #[INV-001] for [amount] is now 14 days overdue. Despite previous messages, I have not received payment or a response.

If I do not receive full payment or a confirmed payment commitment by [date 5 days from now], I will have no choice but to escalate this matter, which may include engaging a debt collection service or legal proceedings.

I strongly prefer to resolve this directly. Please contact me immediately.

Regards,
[Your name]

Phone Scripts

When emails go unanswered, a phone call often resolves the matter instantly. Keep it brief and professional:

Opening:
"Hi [Name], this is [Your name] from [Company]. I'm calling about Invoice #[INV-001] for [amount], which was due on [date]. I wanted to check in to make sure you received it and see when I can expect payment."

If they say it's in the approval queue:
"Thanks for letting me know. Can you give me a specific date when it will be processed? I'd like to mark it in my system."

If they dispute the invoice:
"I appreciate you flagging that. Can you send me the details of your concern in writing so I can address it today? I want to get this resolved quickly for both of us."

If they claim they already paid:
"I don't see it on my end yet — could you send the payment confirmation or reference number? I'll check with my bank immediately."

Escalation Options

If 30 days pass with no payment and no credible commitment, it's time to escalate.

Formal Demand Letter

A formal letter (sent by registered mail or with read-receipt email) stating the amount owed, the original due date, and a final deadline (typically 7 days) before legal action. In many jurisdictions this is a required step before filing a claim.

Small Claims Court

For amounts within your country's small claims limit (€5,000–€10,000 in the EU, £10,000 in England/Wales, $10,000–$25,000 in many US states), small claims court is relatively cheap, fast, and accessible without a lawyer.

Debt Collection Agency

Agencies take 20–40% of the recovered amount as commission. Worth using for invoices you've effectively written off — recovering 60–70% is better than zero.

UK: Statutory Demand and Late Payment Act Interest

The Late Payment of Commercial Debts (Interest) Act 1998 automatically entitles you to statutory interest on overdue B2B invoices — no contract clause required. The rate is 8% above the Bank of England base rate in force on the preceding 30 June or 31 December. With BoE base at roughly 4.5% (mid-2025), that puts the statutory rate at around 12.5% per annum. Formula: daily interest = invoice amount × statutory rate ÷ 365. You can also claim a fixed debt recovery fee: £40 for invoices under £1,000, £70 for £1,000–£9,999, and £100 for £10,000+.

A statutory demand is a separate tool: it puts the debtor on formal notice that you intend to petition for insolvency if the debt exceeds £750 and remains unpaid within 21 days. Courts treat it seriously — use it when a client has the funds but is deliberately stalling.

Note: under the Limitation Act 1980, you have six years from the invoice due date to bring a claim in England and Wales.

EU: Late Payment Directive — Automatic Interest Without a Contract Clause

Under Directive 2011/7/EU, EU businesses are automatically entitled to late payment interest on overdue B2B invoices — the contract doesn't need to mention it. The rate is the ECB reference rate plus 8 percentage points, updated every six months (1 January and 1 July). From 1 January 2026, with the ECB rate at 2.15%, the applicable rate is 10.15% per annum. You're also entitled to a flat €40 compensation fee per overdue invoice to cover recovery costs — claimable in addition to interest.

Payment terms in B2B contracts may not exceed 60 days unless the creditor expressly agrees and the terms are not grossly unfair.

Preventing Late Payments in the First Place

The best way to chase an unpaid invoice is to avoid having one:

Require a deposit (30–50%) before starting work.
Set short payment terms — Net 15 or Net 7 for smaller projects.
Invoice immediately on project completion, not days or weeks later.
Include a concrete due date on every invoice (not just "Net 30").
Set up automated reminders — many invoicing tools send reminders before and after the due date without you having to lift a finger.
Run a credit check on large new clients before committing significant time.

How to Chase an Unpaid Invoice (Scripts & Templates)