Dunning Letter Templates: All 5 Stages, Ready to Copy

A dunning letter is a written notice asking a customer to pay an overdue invoice, and an effective dunning process uses a sequence of them that escalates in tone rather than a single letter. Most B2B teams run five stages: a courtesy reminder, a firm follow-up, a formal notice, a final demand, and pre-collections. Each letter should name the invoice number, the original due date, the exact amount owed, and exactly how to pay. Below are templates for all five stages you can copy and adapt.

The word "dunning" is old, but the problem is not. You delivered, you invoiced, and the money has not arrived. What decides whether you get paid is rarely the wording of any single letter. It is whether a sequence exists at all, and whether it actually goes out on schedule when everyone is busy.

What is a dunning letter?

A dunning letter is a formal written communication sent to a customer with a past-due invoice, reminding them of the outstanding balance and requesting payment. In practice the term covers the whole escalating series, from a soft reminder email a few days after the due date through to a final demand that warns of collections or legal action. The letters get progressively firmer as the invoice ages.

Why is it called a dunning letter?

The term comes from the English verb "to dun," meaning to persistently demand payment of a debt, which has been in use since the seventeenth century. It has nothing to do with a person named Dunning. The name stuck in accounting and ERP software, which is why you will see "dunning levels" and "dunning notices" as configuration options in systems like NetSuite and Sage Intacct rather than the plainer "payment reminders."

What is the purpose of dunning letters?

The purpose is to recover payment while keeping the customer relationship intact. A good dunning sequence does three jobs at once: it removes any excuse that the customer did not know or could not find the invoice, it creates a documented record of your collection attempts should you ever need to escalate legally, and it signals that your business follows up consistently. That last one matters more than people expect. Customers with limited cash pay the suppliers who chase them first.

The 5 stages of the dunning process

Different vendors describe four or five stages. The practical version most B2B finance teams run looks like this. Timing assumes standard net 30 terms.

Send a pre-due reminder three days before the due date as well. It is not technically dunning, since nothing is overdue, but it catches the invoices that were never received or never approved, which is a large share of what would otherwise become stage-one work.

How do you write a dunning letter?

Every letter, at every stage, needs five things: the customer and contact name, the invoice number and original due date, the exact amount outstanding, clear payment instructions including accepted methods, and a specific next step with a date. Letters that reference the precise invoice and amount perform measurably better than generic "your account is past due" messages, because they are impossible to file away as someone else's problem.

Keep the tone respectful even at stage five. The goal is the money, not the satisfaction of being stern, and an account you write off angrily is worth exactly as little as one you write off politely.

Stage 1 template: courtesy reminder

Subject: Invoice [12345] from [Your Company], now past due

Hi [Name],

I hope things are going well. Our records show invoice [12345] for [$amount], dated [invoice date] and due on [due date], is still outstanding. It may simply have been missed, in which case please disregard this note if payment is already on its way.

You can pay by [methods] using the link below, or reply here if you need the invoice sent again.

[Pay invoice link]

Thanks,
[Your name]

Stage 2 template: firm follow-up

Subject: Invoice [12345], [X] days past due, payment date needed

Hi [Name],

Following up on invoice [12345] for [$amount], which was due on [due date] and is now [X] days past due. I have not had a response to my earlier note.

Could you confirm one of two things: the date payment will be issued, or the reason it is being held so we can resolve it. If there is a problem with the invoice, tell me what it is and I will get it corrected today.

[Pay invoice link]

Thanks,
[Your name]

Stage 3 template: formal notice

Subject: Formal notice, invoice [12345] overdue [X] days

[Name],

Invoice [12345] for [$amount], due [due date], remains unpaid [X] days past its due date despite previous reminders on [dates].

Under the payment terms agreed on [contract or PO reference], the account is now subject to [late fee terms], and further orders are on credit hold pending payment.

Please arrange payment within 7 days, by [date]. If payment has already been sent, forward the remittance details and I will apply it.

[Your name], [Title]

Stage 4 template: final demand

Subject: Final demand for payment, invoice [12345]

[Name],

This is a final demand for payment of [$amount] due under invoice [12345], dated [invoice date], payment for which was due on [due date] and is now [X] days overdue.

Reminders were sent on [dates] and no payment or substantive response has been received.

Unless payment in full is received by [specific date, typically 10 to 14 days out], we will place this account with a third-party collections agency, which may affect your commercial credit profile, and we reserve the right to pursue recovery of the debt together with any interest and costs permitted under our terms.

We would much rather resolve this directly. If you are unable to pay in full, contact me before [date] to discuss a payment plan.

[Your name], [Title]

Stage 5 template: pre-collections notice

Subject: Account [number] being placed for collection

[Name],

Despite our final demand dated [date], invoice [12345] for [$amount] remains unpaid.

This account is being prepared for placement with [agency or counsel] on [date]. Payment received before that date will stop the placement.

[Your name], [Title]

Before you go this far, it is worth understanding what recovery actually costs and what your terms entitle you to. Agencies typically work on contingency, and a quick check of how courts have treated late-payment and interest claims in similar commercial disputes will tell you whether pursuing the balance is worth the effort on an invoice of this size. Our guide on when to send an invoice to collections covers the decision in detail, and how much collection agencies charge covers the cost.

How many dunning letters should you send?

Four to six communications before external escalation is the normal B2B range, spread across roughly 60 days. Fewer than four and you are escalating before you have genuinely tried. More than six over the same period stops reading as persistence and starts reading as noise, and customers begin filtering you.

Vary the channel rather than only the wording. A sequence that is five emails from the same address is easy to ignore. A sequence that moves from email to a text message to an actual phone call is not. The stage-three and stage-four moments are where a call does the most work, because that is when you find out whether you are dealing with a dispute, a cash flow problem, or an invoice that never made it into the approval queue. Each of those needs a different response, and no letter will tell you which one you have.

Common mistakes that cost you the money

The letters themselves are rarely the problem. These are:

• Starting too late. Teams that wait until day 30 to send anything have already lost the easiest month of collection.
• Sending to the wrong person. The buyer who signed the PO often has nothing to do with paying it. Get an AP contact on day one.
• Inconsistency. A sequence that runs when someone remembers is worse than a shorter one that always runs, because customers learn quickly which suppliers actually follow up.
• Threatening what you will not do. If stage four warns about collections and nothing happens at day 90, every future letter you send that customer is discounted.
• No record of what was sent. When an account does go legal, the documented trail of attempts is the evidence, and reconstructing it from four people's sent folders is miserable.

Why most dunning sequences quietly stop running

Almost every finance team can write good letters. Very few can send them on the right day, to the right contact, for every open invoice, every week, while also closing the month. The sequence survives contact with a busy quarter for about three weeks, then someone's out sick and it lapses, and the aging report starts creeping right.

That is the actual argument for automating it. Templated dunning levels in your ERP handle part of the job, but they generally stop at email and still need someone to work the exceptions. An automated dunning management agent runs the whole ladder without anyone remembering to press send, escalating from email to SMS to a live phone call as the invoice ages, then applying the payment when it lands. For the broader picture of what that covers, see our explainer on what dunning is and the wider collections automation approach. If you would rather script the conversation than the email, our collections call script covers the phone stage.

The bottom line

Good dunning letters are specific, escalate on a predictable schedule, and always give the customer an easy way to pay right now. Use the five templates above as your ladder, set the send dates in advance rather than deciding case by case, and change channel as the invoice ages instead of just changing adjectives. The businesses that get paid fastest are not the ones with the most eloquent letters. They are the ones whose second and third letters actually go out.