Unpaid Invoice Reminder Email With Strict Deadline

When an invoice remains unpaid past its due date, a straightforward email with a strict deadline gets the fastest results. Use this reminder to set a clear expectation for immediate payment or a confirmed new due date with your client.

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Starter

$39

One-time payment for a basic reminder pack.

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Pro

$89

Full multi-email sequence plus templates and variations.

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When to use / when to send

Checklist / what to include

Reference to invoice #{{InvoiceNumber}} and total amount {{Amount}}
Original due date {{DueDate}}
One clear ask: pay now or confirm a new date
Pay link {{PayLink}}
Concrete reply-by deadline {{ReplyByDate}}
Your contact closing: {{YourName}}/{{Company}}

How to use

Copy/paste template

Hi {{ClientName}},

Invoice #{{InvoiceNumber}} for {{Amount}} was due {{DueDate}} and remains unpaid.

Please complete payment via {{PayLink}} or reply with the exact date payment will be released.

If we do not have payment or a new date by {{DueDate}}, we’ll move to the next step in our process.

Thanks,
{{YourName}}
{{Company}}

Follow-up plan + common mistakes

If a date is provided, confirm back and track it strictly.
If there’s no reply by {{ReplyByDate}}, escalate or change collection method.
Don’t send multiple soft reminders—one clear deadline is effective.
Don’t get drawn into side discussions—stick to payment or date.
Avoid adjusting the deadline once it’s set—consistency builds credibility.

FAQ

Yes—clients respond faster when expectations are clear and they know escalation will follow if ignored.