Lenny learned that the slow way. He sent an invoice on 30-day terms, told himself the customer was busy, then very busy, and got paid on day 94. The 90-second film above follows his mistakes one by one. This article turns them into three rules you can apply to your own overdue invoices this week. You can also watch it on YouTube.
Why waiting to chase costs you money
An unpaid invoice does not stay still: every week it sits, it gets harder to collect.
- It drops down their list. Customers pay the suppliers who ask. A quiet supplier is paid last.
- Silence looks like agreement. If you say nothing on day 31, the customer assumes the new date suits you.
- People and paperwork move on. The buyer who placed the order changes jobs, the delivery note goes missing, and a dispute appears that nobody raised at the time.
- Trouble surfaces late. A customer in difficulty usually pays the loudest creditors first.
We put numbers on this in the cost of delaying debt collection and in what unpaid international invoices do to your balance sheet.
Rule 1: Chase the day after the invoice is due
The first reminder goes out the morning after the due date, not on day 60. It tells the customer you track your invoices, and it catches the honest problems early: a wrong purchase order number, an invoice sent to the wrong inbox, a missing bank detail.
A chasing schedule that works for most B2B invoices:
- The day before it's due: a friendly heads-up with the invoice attached.
- Day 1 overdue: a short written reminder (template below).
- Day 7: a phone call to the person who approves payments, then an email confirming what they said.
- Day 14 to 21: a firmer written reminder with a clear deadline, and a note of any late-payment interest your contract or local law allows.
- Day 30 to 60: a formal final notice, such as a letter before action, then hand it over (Rule 3).
Put these dates in your calendar the day you send the invoice, so chasing becomes routine rather than a mood. Done this way, chasing protects the relationship: see how to collect a debt without losing the client.
Rule 2: Put every reminder in writing
Every reminder should state three things: the amount, the date it was due, and the date you now expect payment. Lenny's email had three exclamation marks and no deadline. A good reminder has the opposite: no exclamation marks and one specific date.
- Amount: the exact sum, currency and invoice number.
- Date: the original due date, so there is no debate about how late it is.
- Deadline: a calendar date for payment, usually 7 days out, and how to pay.
Keep the paper trail too: the signed order or contract, proof of delivery, and a log of every call and email. These are the first documents a collection agency, lawyer or court will ask for. Clear terms at the start make all of this easier; our guide to international payment terms for B2B covers what to put in the contract.
Rule 3: Still unpaid by day 60? Hand it to a professional
If two months of polite, written reminders have produced nothing but "it's in the system", the problem is no longer a forgotten email. That phrase is a classic stalling line; here is how to recognise and counter stalling tactics.
At that point a professional collection agency usually gets further, faster, than another reminder from you:
- A different voice. A letter from a collection agency changes the customer's priorities.
- Local reach. When the customer is abroad, an agent who works in their language, time zone and legal system knows which steps are realistic there.
- Your time back. You stop chasing and go back to selling.
Day 60 is a rule of thumb, not a legal deadline. For the full timing question, read how long to wait before hiring a collection agency, and for what the process looks like, what happens when you send a debtor to collections. As a general rule, the longer you wait, the less you usually get back.
Late-payment rules in the EU and the UK
In both the EU and the UK, the law usually lets you charge interest on late B2B invoices, so a late customer costs you more than the invoice itself.
| EU (Late Payment Directive) | UK (Late Payment Act) | |
|---|---|---|
| Default payment term | 30 days unless the contract says otherwise | Set by the contract today; a 30-day implied term is proposed |
| Longer terms | Up to 60 days if both sides agree; beyond 60 only if expressly agreed and not grossly unfair | A 60-day cap is proposed for most B2B contracts |
| Late-payment interest | Reference rate plus at least 8 points | 8% above Bank of England base rate |
| Fixed compensation | At least €40 per late invoice | £40 or 1% of the contract price for disputes raised late (proposed) |
| Status, November 2026 | In force; a proposed 30-day cap has not been adopted | Commercial Payments Bill before Parliament since May 2026 |
Each EU country applies the directive through its own national law, so details vary. Check the rules in your customer's country before you claim interest or compensation; our country guides for the UK, Germany and France are a good start.
Template: the day-one reminder email
Copy this, fill in the brackets, and send it the morning after the due date.
Subject: Invoice [number] – [amount] – due [date]
Hello [name],
Invoice [number] for [amount and currency] was due on [due date] and we have not yet received payment.
Please arrange payment by [date, 7 days from today] to:
[bank details or payment link]
If the invoice has already been paid, please send the remittance details. If anything is blocking payment, such as a missing purchase order number, reply and we will fix it today.
Thank you,
[your name]
[phone number]No exclamation marks, no apology, one deadline.
Customer in another country?
The three rules are the same, but the follow-through is not. Language, time zones and local law all slow a cross-border chase down. Our guides on chasing overdue invoices from overseas customers and on a foreign debtor ignoring your emails and calls pick up where this article stops.
Frequently asked questions
How long should I wait before chasing an unpaid invoice?
One day. Send a short written reminder the morning after the due date, then follow a fixed schedule: a phone call at day 7, a firmer reminder at day 14 to 21, and a formal final notice between day 30 and day 60.
Is it rude to chase an invoice straight away?
No. A short, polite, factual reminder the day after the due date is normal practice in B2B. Waiting weeks and then sending an angry email is what damages relationships.
The customer says the invoice is "in the system". What now?
Ask for a payment date in writing and the name of the person who approves the payment. If that date passes, move to a formal notice.
When should I use a collection agency?
Usually when written reminders have failed for around 60 days. Hand it over sooner if the customer stops answering, raises a dispute they never mentioned before, or is in another country where you cannot act locally.
What if my customer is in another country?
Keep every reminder in writing and keep proof of delivery. Rules on interest, formal notices and courts differ by country, so a local agent who works in the customer's language and legal system saves time.
Invoice still unpaid?
If you have passed day 60, or your customer is in another country, InterStation's local agents can take it from here, through amicable collection first: same country, same language and same time zone as your customer.
Contact Us, Free Review. Send us the invoice and the paper trail, and we will tell you what is realistic before you commit to anything.
General information, not legal advice. Payment terms, interest and collection rules vary by country and by contract.