Payment Reminder Email Subject Lines That Get Opened (30 Examples)

Your subject line decides whether the reminder gets opened, forwarded to accounts payable, or archived. Clear beats clever: invoice number, amount or status, and the action needed.

Before the due date

• Invoice [#] due [Date]
• Friendly reminder: invoice [#] due Friday
• Payment link for invoice [#]
• Upcoming: invoice [#] ([Amount])
• Who should receive invoice [#]?

Just past due (1-14 days)

• Quick check-in on invoice [#]
• Invoice [#] was due [Date]
• Did invoice [#] reach you?
• Following up: invoice [#]
• Payment date for invoice [#]?
• Invoice [#]: anything holding it up?

30-60 days

• Invoice [#] is now 30 days past due
• Action needed: invoice [#] ([Amount])
• Second reminder: invoice [#]
• Please confirm payment date: invoice [#]
• Late fee now applies to invoice [#]
• Payment plan option for invoice [#]

Final notices

• Final request: invoice [#] ([Amount])
• Final notice before [next step]: invoice [#]
• Pausing work until invoice [#] is paid
• Response needed by [Date]: invoice [#]
• Last reminder before escalation: invoice [#]

Proposals and quotes

• Any questions on the [Project] proposal?
• Quick idea for [Project]
• Should I close the file on [Project]?
• Still a priority for [Quarter]?
• Smaller first phase for [Project]?
• Hold your [Start Date] start?
• Contract for [Project]: ready to sign
• Next steps from our call

Subject line rules

• Include the invoice number so AP can search it.
• Avoid ALL CAPS, "URGENT!!!", and vague lines like "Following up".
• Escalate specificity (days overdue, deadline), not volume.

Free mini-pack: 3 more follow-up templates (HTML + PDF), no signup.

Related guides

• Second payment reminder email
• Invoice 30 days overdue email
• Invoice due soon reminder email
• Client not responding after proposal
• Invoice follow-up email templates

Practical communication guidance only, not legal advice. Payment terms, late fees, and collection options depend on your contract and jurisdiction.