How to Follow Up on an Unpaid Invoice

An unpaid invoice is not a moral failure on the client's part and it is rarely a sign of fraud. Most of the time the person who approved your work and the person who releases payment are two different people, and the invoice fell into a gap between them. Your job when you follow up is to close that gap quickly, professionally, and without burning the relationship you will probably want again next quarter.

The single biggest mistake freelancers and small suppliers make is waiting too long to start. A reminder sent the day after the due date reads as routine bookkeeping. The same reminder sent three weeks later reads as a complaint, and by then the invoice has slipped to the bottom of an accounts-payable queue where it can sit for months. Following up early and on a fixed schedule is what separates suppliers who get paid in 35 days from suppliers who get paid in 75.

This guide lays out a reminder sequence keyed to specific days: day 1, day 7, day 14, day 30, and day 60. It gives you the email templates to send at each step, the moment to switch from email to a phone call, and the point where a collection agency or formal demand becomes the right move. The whole sequence is built to stay calm at every stage, because calm collectors get paid faster than angry ones.

Start the clock the day after the due date

Before you send anything, be certain the invoice is actually overdue. If your terms are Net 30, the due date is 30 days after the invoice date, and the payment is late only once that day has passed. If you are unsure exactly when an invoice falls due, the Invoice Due Date Calculator works it out from the invoice date and your payment terms, and our guide on how to write payment terms on an invoice covers how to state those terms so they are unambiguous in the first place.

Once the due date has genuinely passed, send the first reminder the next morning. Speed here is not aggression. It signals that you run a tight ledger and that invoices to you do not get to age quietly. Clients who deal with a supplier that follows up at day 1 learn to pay that supplier first.

The day-1 email: assume the best

The first message assumes the client simply forgot. No interest, no threats, no edge in the tone. You are giving them the easiest possible path to pay.

Subject: Invoice 1043 - friendly reminder

Hi Dana,

Quick note that invoice 1043 for $2,400 was due yesterday, 14 June. It may have slipped through, which happens. You can pay through the link below or by bank transfer to the details on the invoice.

[Pay invoice 1043]

Happy to resend the PDF if it is easier. Thanks so much.

Sam

Notice what the template does. It names the invoice number and amount so nobody has to dig. It gives one clear payment action. It offers to resend the document, removing the "I can't find it" excuse. And it closes warmly. Roughly half of late invoices clear within a few days of a message like this.

Day 7 and day 14: firmer, still professional

If a week passes with no payment and no reply, send a second reminder. The tone shifts from "you forgot" to "this needs your attention," but it stays courteous.

Subject: Invoice 1043 now 7 days overdue

Hi Dana,

Following up on invoice 1043 for $2,400, now seven days past its 14 June due date. Could you let me know the expected payment date, or flag if anything is holding it up on your end? Payment link below.

[Pay invoice 1043]

Thanks, Sam

The day-7 note introduces two new things: a request for a specific payment date, and an open door for the client to raise a problem. That second part matters. A surprising share of "late" invoices are actually quiet disputes, a line item the client questions, a PO number missing from your invoice, an approver on leave. Asking "is anything holding it up?" surfaces those before they fester.

At day 14, send a third reminder and, if your terms or local law allow it, mention that late payment interest may now apply. This is the moment to be precise rather than vague. Tell the client the rate and the basis. In the UK, the Late Payment of Commercial Debts Act lets a supplier charge the Bank of England base rate plus 8 percent plus a fixed compensation fee; across the EU the Late Payment Directive sets interest at 8 percentage points over the ECB rate. To produce the exact figure for the invoice in front of you, run it through the Late Payment Interest Calculator, which applies the right statutory rule for the UK, EU, India, and other jurisdictions.

Subject: Invoice 1043 - 14 days overdue, interest now applies

Hi Dana,

Invoice 1043 ($2,400) is now two weeks overdue. Under our terms, statutory late-payment interest applies from the due date, currently adding about $9 so far. I would much rather close this out without the interest mounting. Can you confirm a payment date this week?

[Pay invoice 1043]

Sam

Day 14 to day 30: pick up the phone

By the time an invoice is two to four weeks overdue and three written reminders have gone unanswered, email has stopped working. A phone call does two things an email cannot: it forces a real-time answer, and it tells you the actual reason for non-payment.

Keep the call short and specific. Confirm the invoice number, ask directly when payment will be made, and listen. If the client admits a cash-flow squeeze, you can negotiate a payment plan, which is far better than a balance that sits indefinitely. If they mention a dispute, you now know what to fix. If they promise a date, get it in writing immediately afterward.

That written follow-up is the rule that protects you. Always send a short recap email after any call: "Thanks for the call just now. To confirm, you will pay invoice 1043 in full by 5 July." This converts a verbal promise into a documented commitment, which matters a great deal if the matter later goes to a demand letter or court.

Day 30 and day 60: the demand letter and beyond

If the invoice crosses 30 days overdue with no resolution, send a formal demand letter, sometimes called a final notice or letter before action. This is the bridge between informal reminders and formal enforcement, and its tone is deliberately different: factual, dated, and explicit about consequences.

A demand letter should state the original invoice and amount, the dates of every prior reminder, the interest accrued to date, and a firm deadline (commonly 7 to 14 days). It should say plainly what happens if that deadline passes: referral to a collection agency, or a claim filed in small-claims or commercial court. Keep it unemotional. A demand letter is evidence, and a judge reading it later should see a reasonable supplier, not an angry one.

When the deadline in the demand letter passes, you have two routes. A collection agency takes the matter off your desk in exchange for a cut of what it recovers, usually 10 to 50 percent depending on the age and size of the debt, which makes it worthwhile mainly on larger balances. The court route, through small-claims or its local equivalent, keeps the full amount but costs you time and a filing fee. If you go that way, our guide on business days in court filings explains how filing deadlines and day-counting actually work, and the companion guide on what to do when a client won't pay walks through the escalation ladder in detail.

Build the sequence into your invoicing, not your memory

The reason most suppliers do not follow this schedule is not that they disagree with it. It is that day-1, day-7, and day-14 reminders are easy to forget when you are busy delivering the next project. The fix is to automate the reminders so they fire on schedule whether or not you remember. Modern invoicing tools send the polite nudges for you, apply late fees automatically, and show you an aging report so no invoice silently slips to 90 days. Set the cadence once and the system does the chasing.

FAQ

How long should I wait before following up on an unpaid invoice?

Send a polite confirmation the day after the due date passes, not a week later. A short reminder at day 1 sets the tone that you track your receivables closely. Most late payers are simply disorganized, and a same-week nudge resolves the majority of cases before they harden into disputes.

What should the first reminder email say?

Keep it factual and friendly. State the invoice number, the amount, the original due date, and a single clear payment link or set of bank details. Do not apologize for asking and do not threaten anything yet. The day-1 email assumes the client meant to pay and simply forgot.

When should I start charging late payment interest?

Once the invoice is genuinely overdue and your terms or local statute allow it, usually from the day after the due date. In the UK that is the Bank of England base rate plus 8 percent under the Late Payment of Commercial Debts Act; in the EU it is 8 points over the ECB rate. Use the Late Payment Interest Calculator to compute the exact figure for your jurisdiction.

When is it time to call instead of email?

Around day 14 to day 30, after two or three written reminders have gone unanswered. A phone call surfaces the real reason for non-payment, whether that is a cash-flow problem, a lost invoice, or a quiet dispute. Always follow the call with a short written summary so the conversation stays on the record.

When should I hand an invoice to a collection agency?

Once the invoice is 60 to 90 days overdue and your own escalation ladder has stalled. Agencies typically take 10 to 50 percent of what they recover, so the math only works on larger balances. Before you hand it over, send one final demand letter stating that collection or legal action follows if payment does not arrive by a set date.

Can I charge a late fee if I didn't mention it on the invoice?

It is much harder. A late fee or interest clause is enforceable when it appears in your contract or on the invoice before the work was accepted. Many jurisdictions still grant statutory interest even when the contract is silent, but a contractual fee you never disclosed is easy for a client to refuse. Put the clause on every invoice from the start.

A late invoice is a process problem, not a personality test. Work the schedule, keep every message on the record, and escalate on fixed dates rather than on how annoyed you feel. Suppliers who treat collections as routine administration, handled the same way every time, get paid faster and keep more clients than those who let invoices age and then explode.