Payment reminder letter templates for B2B invoices

A payment reminder letter is a formal written notice that an invoice is due or already overdue, asking the customer to pay by a specific date. It states the invoice number, the amount, and the deadline, then gives a clear way to settle it. Unlike a quick email, a letter carries formal weight and creates a written record.

For most B2B invoices, an early reminder is a courtesy that keeps good accounts current and a firmer one is a prompt that gets a slow payer moving. The templates below cover both: a before-due reminder that heads off lateness, and an after-due reminder that asks for action without yet escalating to a demand. Fill the placeholders, keep the tone professional, and route any dispute or promise to pay to a person rather than the next letter.

When a formal reminder letter makes sense

A letter is not the default channel for every reminder. Email is faster and easier to act on, so it handles most routine nudges. A formal letter earns its place in a few specific situations:

• An email reminder went unanswered, and you want to raise the formality a notch.
• The contract or account requires written notice before any further step.
• The invoice is high value, and a letter signals you are treating it seriously.
• You want a clean paper trail for an account that may escalate later.

Used well, a letter sits between a casual email and an overdue invoice letter. It is firmer than a reminder email but still cooperative, not yet a demand.

Before-due and after-due letter templates

The two templates below cover the most useful moments: just before the due date, and shortly after it passes. Each pairs with a note on when to send it.

Before-due reminder letter

[Date]

[Customer name]
[Customer address]

Re: Upcoming payment, invoice [Invoice number]

Dear [Contact name],

This is a courtesy reminder that invoice [Invoice number] for
[Amount] is due for payment on [Due date].

To keep your account current, please arrange payment on or before
that date. You can pay using any of the options below:

  - Online: [Payment link]
  - Bank transfer: [Bank details]
  - Check payable to: [Company name], [Address]

If you have already scheduled this payment, thank you. If you have
any questions about the invoice, please contact us at [Phone] or
[Email].

Sincerely,
[Your name]
[Company name]
[Phone] | [Email]

When to use this: a few days before the due date, to keep a current account on track and prevent it from slipping past due.

After-due reminder letter

[Date]

[Customer name]
[Customer address]

Re: Payment now due, invoice [Invoice number]

Dear [Contact name],

Our records show that invoice [Invoice number] for [Amount], due
on [Due date], has not yet been paid and is now [Days overdue]
days past due.

We would appreciate payment of [Amount] by [New due date]. You can
settle the balance using any of the options below:

  - Online: [Payment link]
  - Bank transfer: [Bank details]
  - Check payable to: [Company name], [Address]

If payment is already on its way, please disregard this letter. If
there is anything holding it up, contact us at [Phone] and we will
be glad to help.

Sincerely,
[Your name]
[Company name]
[Phone] | [Email]

When to use this: within a week or two of the due date, when a balance has slipped but the relationship is still cooperative.

Structuring the letter for clarity

A reminder letter works when the customer can read it once and know exactly what to do. Lead with the invoice number and amount so there is no ambiguity. State the deadline as a real date, not "promptly." List the ways to pay in a clean block the customer can scan. Close with a line that invites a reply if something is wrong.

Keep it to a single page and a handful of short paragraphs. The customer is looking for the number, the date, and the link. Anything else competes with those three and slows the response. Professional and plain beats wordy and formal.

Adding payment options and urgency

Make paying the easiest thing the customer can do. List every method you accept, lead with the fastest one, and put a clickable or clearly printed payment link near the top. Friction here costs you cash, because a customer who has to hunt for bank details often defers the whole task.

Add urgency through the deadline, not through pressure language. A specific date the customer has agreed to, by terms, creates more movement than a stern tone. If the invoice is genuinely aging, the after-due letter can note that the balance is now past due and ask for action by a clear new date. Save heavier consequences for the escalation steps that come later.

Moving from letters to multi-channel

A letter is one channel, and on its own it is slow. The strongest reminder programs use the letter for formal weight and pair it with faster channels for reach. An email lands instantly and carries the payment link. A short text nudges the customer to open it. The letter backs all of that with a written record.

Keep the message consistent across channels: same invoice, same amount, same deadline, same link. A customer who gets a letter, an email, and a text that all say the same thing reads it as one organized account team, not three disconnected chases. For the email and sequence side of this, see the payment reminder email sequence and the broader collection email templates.

How Rex sends reminders where they land

Running formal reminders by hand means tracking which invoice is approaching its date, which has slipped, which contact to write to, and which channel each customer actually reads. Across a full ledger, that coordination is the work that quietly does not happen, so reminders go out late or not at all.

Rex sends each reminder on the channel the customer responds to, at the right point in the invoice's life. It pairs the formal notice with email and a short text where that helps, keeps every message accurate to the live balance, and stops the cadence the instant a customer pays, disputes, or promises a date. The team only sees the accounts that need a human decision.

See how Rex delivers reminders across every channel, end to end.