Dunning letter templates: free examples for every overdue stage

A dunning letter is a formal written notice telling a customer that an invoice is overdue and asking for payment by a set date. Dunning letters come as a series that escalates in tone, from a polite first notice to a final demand that states exactly what happens if the balance stays unpaid. They create a paper trail that shows you pursued the debt in good faith.

Below are copy-ready templates for every rung of the dunning ladder: first, second, and third notices, plus a final demand. Fill in the [Placeholders], keep the facts accurate, and send each one at the right age. The day counts assume net-30 terms.

What a dunning letter is and when to send one

A dunning letter is the written, formal cousin of a collection email. Where an email is quick and conversational, a letter is structured, dated, and built for the record. Many AR teams send the early reminders by email and reserve formal letters for the later stages, when a documented trail starts to matter. Others send both, with the letter as the authoritative version and the email as the nudge.

You send the first dunning letter once an invoice passes its due date and an initial reminder has not landed. From there, each letter goes out at a defined interval as the balance ages. The series has two jobs. The first is to get the invoice paid, which most of them do. The second is to build evidence that you asked, clearly and repeatedly, before escalating, which protects you if the matter ever reaches a collections agency or a court.

First, second, and third dunning letter templates

First dunning letter (friendly reminder)

The first letter assumes the customer simply overlooked the invoice. Keep it courteous.

[Company name]
[Company address]
[Date]

[Customer name]
[Customer address]

Re: Overdue invoice [Invoice number]

Dear [Customer name],

Our records show that invoice [Invoice number], dated [Invoice date] for [Amount], was due on [Due date] and remains unpaid.

We understand this may simply have been overlooked. Please arrange payment of [Amount] at your earliest convenience. You can pay online at [Payment link] or by [Other payment method].

If you have already sent payment, please accept our thanks and disregard this letter. If you have any questions about the invoice, contact us at [Phone or email].

Yours sincerely,
[Your name]
[Title]
[Company name]

When to send this: 3 to 7 days past the due date, as the first formal notice.

Second dunning letter (firm reminder)

The second letter is firmer and references the first. It asks for a specific commitment.

[Company name]
[Company address]
[Date]

[Customer name]
[Customer address]

Re: Second notice, overdue invoice [Invoice number]

Dear [Customer name],

We wrote to you on [Date of first letter] regarding invoice [Invoice number] for [Amount], due on [Due date]. As of today, the balance is [Days overdue] days overdue and remains unpaid.

Please arrange payment of [Amount] by [New due date]. You can pay at [Payment link] or by [Other payment method].

If you are unable to pay in full by that date, please contact us at [Phone or email] to discuss a payment arrangement. We would prefer to work with you than to let this balance age further.

Yours sincerely,
[Your name]
[Title]
[Company name]

When to send this: around 15 to 30 days past due, after the first letter went unanswered.

Third dunning letter (escalation notice)

The third letter raises the stakes and names the consequence that is coming.

[Company name]
[Company address]
[Date]

[Customer name]
[Customer address]

Re: Third notice, urgent: overdue invoice [Invoice number]

Dear [Customer name],

Despite our notices of [Date of first letter] and [Date of second letter], invoice [Invoice number] for [Amount] remains unpaid and is now [Days overdue] days overdue.

We require payment of [Amount] in full by [Final due date]. Please pay at [Payment link] or by [Other payment method].

If payment is not received by that date, your account may be placed on hold and this matter may be escalated for further collection action. We urge you to contact us at [Phone or email] today if there is a dispute or a reason for the delay we should know about.

Yours sincerely,
[Your name]
[Title]
[Company name]

When to send this: around 45 to 60 days past due, as the last notice before a final demand.

Final demand letter template

The final demand is the last letter before you refer the account to collections or legal action. It states the consequence plainly and puts a firm deadline on it.

[Company name]
[Company address]
[Date]

[Customer name]
[Customer address]

Re: FINAL DEMAND, overdue invoice [Invoice number]

Dear [Customer name],

This is a formal final demand for payment of invoice [Invoice number] for [Amount], originally due on [Due date] and now [Days overdue] days overdue. We have written to you on [Date of first letter], [Date of second letter], and [Date of third letter] without receiving payment or a response.

You must pay the full outstanding balance of [Amount] by [Final due date].

If payment in full is not received by that date, and you have not contacted us to arrange terms, we will refer this debt to [Collections agency name or legal step] on [Escalation date], without further notice. This may add recovery costs and interest to the balance you owe.

To resolve this now, pay at [Payment link] or contact us immediately at [Phone or email].

Yours sincerely,
[Your name]
[Title]
[Company name]

When to send this: at 60 to 90 days past due, as the documented final demand before third-party referral.

Legal and compliance considerations

A dunning letter is not a court order, but it carries weight as evidence. Keep these in mind so your letters help rather than hurt:

• State only facts you can back up. The invoice number, amount, dates, and prior notices should all be accurate. An error in a final demand undercuts the whole trail.
• Only threaten what you will actually do. If you say you will refer the debt on a date, be prepared to do it. Empty threats train customers to ignore you and can expose you to claims of bad faith.
• Avoid harassment. Do not use abusive language, do not contact at unreasonable hours, and do not contact third parties about the debt. Many jurisdictions regulate how businesses can pursue payment, so check what applies to you.
• Keep copies and dates. The value of the ladder is the record. Log when each letter went out and to whom.
• Mind interest and fees. Only add late fees or interest your contract or local law allows, and state the basis if you do.

Match the tone to the stage. Sending a final demand at day three reads as a threat and burns the relationship. Sending a friendly reminder at day ninety signals the debt is not serious. For more on calibrating that gap, see the guide on a friendly first reminder versus a final notice.

Letters vs modern dunning

Formal letters still have a place, mainly for the documented trail in the later stages and for customers who respond to paper. But as a primary collection tool, static letters have real limits. They are slow. They go out on a fixed schedule that ignores how each customer actually behaves. They cannot tell that a customer paid yesterday, or raised a dispute last week, so they keep marching down the ladder regardless.

Modern dunning replaces the rigid letter series with an adaptive, multi-channel cadence. Instead of one tone for every account at a given day count, it varies the message, the channel, and the timing to fit each customer's history and risk. Email handles the routine majority. A letter or a call comes in only where it adds weight. For how this works as an email cadence, see the guide on building a dunning email sequence, and for the email versions of these notices, the dunning email templates.

How Rex automates the full dunning ladder

A static dunning ladder forces a choice: either someone manually drives every letter at every stage across the whole ledger, or you accept a one-size-fits-all schedule that fits no customer well. Both cost you. The manual route eats the team's week. The rigid route sends a third notice to a customer who already disputed the invoice, or a final demand to one who paid two days ago.

Rex runs the ladder as adaptive, multi-channel dunning. It tracks every invoice's age, sends the right notice on the right channel for each account, and hardens tone on its own from first reminder through final demand, without anyone driving the schedule. It reads replies, so it pauses the moment a customer disputes a charge or promises a date, and routes those to a person with the full history. When payment lands, it stops. The formal trail still exists where it matters, but you are no longer mailing letters down a calendar. Your team handles only the accounts that need a human decision.

See how Rex runs the full dunning ladder across your whole ledger.