A follow-up gets paid when it is easy to act on and impossible to misread. Structure decides that long before tone does. Send three emails: the day after the due date, a week later, and two weeks after that, each one shorter than the last. Each carries the invoice number, the amount as the customer already saw it, the original due date, one pay-now link, and one question with a yes-or-no answer. The version that writes itself is in How to use AI to chase unpaid invoices politely; this is the one you write by hand.
Intuit's 2026 Small Business Late Payments Report found 59 percent of small businesses had invoices overdue by more than 30 days, up from 47 percent the year before. Xero's own data put the average US late payment at 8.5 days past the due date in the June 2026 quarter, with customers taking 29.3 days to pay. Both are associations across many businesses. Neither proves that any single email fixes anything. They do say that late invoices are ordinary, and that asking for money is a normal part of being paid.
The three emails each have one job
Email one is a convenience. It assumes the invoice was forgotten and hands over everything needed to pay without a search through the inbox. Email two is the diagnosis. It drops the good-faith assumption, asks the one question, and gives a way out that costs the customer one line of typing. Email three is notice: it says what you will do next, which is call, and stops being a request.
Each email is shorter than the one before it. That is not style. A long chase reads as a negotiation, and a negotiation invites a reply about the project and the budget. Three lines about an invoice get answered with a date.
What the three emails say
Exhibit 1
The sequence is designed to end at the second email, because the third is procedure
Put the invoice and its state in the subject line, because an inbox is sorted by subject line before it is read. Write "Invoice [1042] is seven days past due". A subject like "Following up" leaves the reader nothing to sort by, and a project name hides that money is owed.
The first email, sent the day after the due date:
"Hi [name], invoice [1042] for [amount] was due yesterday. I have attached the PDF again in case it got buried. If payment is already scheduled, ignore this. If anything is holding it up, say so and I will sort it today. Thanks, [your name]"
The second, a week later:
"Hi [name], invoice [1042] for [amount] is now eight days past due and I have not seen it come through. Is something blocking it, a missing PO number, or the wrong contact on the invoice? One line tells me what to fix. The pay link is below."
The third, two weeks after that:
"Hi [name], invoice [1042] is fourteen days past due. I will call [day of the week] to get a payment date for it. If it is already on its way, reply with one line and the call does not happen."
No apologies in any of them. You did the work, the terms were agreed before the work started, and "sorry to bother you again" tells the reader that you are not entitled to the money.
Why "just checking in" never works
It gives the reader nothing to act on. A follow-up with no invoice number, no amount and no date asks the customer to rebuild the transaction from memory, then decide whether a reply is worth the effort. A reply that gets put off is where unpaid invoices live.
The opening sentence should assume good faith once, and only once. Email one can say it slipped. Email two cannot, because you have already given them the invoice and the link. Repeating the apology in email three tells a customer who has ignored two emails that a third will be ignored too.
What goes in every follow-up
Exhibit 2
A paid follow-up carries five facts and one ask, and it carries no new information
What goes in: the invoice number, the amount exactly as they saw it, the original due date, the PDF attached again, one pay-now link, and one question answerable with yes or no. Attach the PDF every time. A forwarded email loses its attachment, and a colleague answering on a phone cannot go hunting for the number you want paid.
What stays out: apologies, "just checking in", new information about the project, renegotiated terms, and threats. A follow-up that mentions scope or milestones turns an invoice into a discussion, and discussions take weeks. Save those for a call.
The one question does most of the work
"Is anything blocking payment?" converts a chase into a support ticket, and support tickets get answered. The answers are boring and fixable: the PO number was missing, or the invoice went to a contact who left. A finance team that processes payments on one fixed day a month explains a delay too, and it costs you nothing to find that out.
That question is also your early warning. A customer who replies "the PO number is wrong" wants to pay you. A customer who ignores a question they can answer in a line is not answering. Email three is how you get an answer.
The phone call at the third touch
Email three announces the call, so the call is expected. Call the named contact, ask for a date, write it down, and send one email after confirming it. The emails are the record; the call is where the date comes from.
A net-30 invoice dated Tuesday, October 13, 2026 falls due Thursday, November 12, 2026, so a reminder set for three days after lands on a Sunday, which is why the day of the week you invoice matters more than it looks. Invoice midweek and chase midweek.
What the law does and does not do here
The Fair Debt Collection Practices Act regulates debt collectors, people whose business is collecting debts, or who regularly collect debts owed to someone else. A debt under the rule is a consumer's obligation, and a consumer is a natural person, so a company invoice is not the kind of debt it defines. Invoicing your own customer in your own name keeps you outside that definition. It does not license theatrics: using a name that makes the email look as though a collection agency is involved puts a creditor inside it.
Late fees come out of the contract. An email cannot create one. In California, interest on a late payment is whatever your contract says, and where the contract is silent the state supplies a default rate of 10 percent a year. Rules like that are written state by state, so the one that applies to you is yours. Everywhere, the fee has to be in the paperwork before the work starts. A number invented after an invoice goes past due has nothing behind it, and it weakens every other line on your paperwork.
What the tools already automate
QuickBooks Online sends reminders on its own, timed a few days before or after the due date and schedulable up to 90 days either side. The catch is that they go out only for invoices you emailed from QuickBooks, so an invoice delivered any other way is never chased. Wave sends reminders only if you accept online payments or subscribe to its Pro Plan, at the due date and 3, 7 and 14 days after it, and to the one primary email on the customer record, so a second contact gets nothing. Stripe sends reminders before, on, or after the due date for one-off invoices, and its hosted invoice page is what makes a pay-now button inside your email work. For the wider choice, see QuickBooks vs Xero vs Wave for a small service business.
Tools send reminders on their own. Emails two and three need your own hands. The same Intuit report found 55 percent of businesses on net-30 terms had overdue invoices, against 26 percent of those that require immediate payment. That is an association across many businesses, so shorten your terms where your work allows it.
The end of the road
A final notice states the amount, the age of the debt, and one deadline, then stops. Small claims is the next step. Florida's limit is $8,000, not counting costs, interest and attorneys' fees; California lets a business claim up to $6,250. Neither court collects the money for you if you win, so collection stays your job after the judgment.
Exhibit 3
The sequence should stop at the phone call, because everything past it costs more than the invoice
The tax side decides how much this is worth chasing. The IRS allows a bad debt deduction only if you already counted the money as income, which is why an unpaid invoice is usually not deductible for a cash-basis business. To claim it you have to show the debt is worthless and that you took reasonable steps to collect it. Your three emails are part of that record. See what clean books look like: a monthly bookkeeping rhythm.
The best follow-up is the invoice you sent correctly the first time
Right contact, named, with the email address that processes payments. PO number on the face of the invoice if they use one, because a missing PO number can leave an invoice sitting in a queue. Terms stated on the invoice and in the agreement that preceded it. See writing quotes and proposals that get answered and the simple client-onboarding checklist that captures the billing contact before work starts.
The sequence as a checklist
- Email one, day one past due: invoice number, amount, due date, PDF, pay-now link, "is anything blocking this?"
- Email two, a week later: the same five facts, shorter, no apology, one yes-or-no question.
- Email three, two weeks after that: amount, age, the call you are making, and the reply that stops it.
- After the call: one email confirming the date you were given.
- Every time: attach the PDF, keep the ask to one line, add nothing new about the project.
When the chasing turns into a weekly job, our bookkeeping work covers invoicing and receivables along with the records behind them: bookkeeping for small firms.