How to Write a Past Due Invoice Email That Gets Results

An invoice becomes past due the day after its payment deadline. If your terms are Net 30 and you invoiced on February 1, the invoice is past due starting March 4. In the US, if no payment terms are stated, most states default to 30 days from invoice date — but it's always safer to put explicit terms on your invoice. FreshBooks reports freelancers spend an average of 1.5 days per month chasing late payments, and the US Federal Reserve Small Business Credit Survey found 27% of SMBs report late payments as a top cash flow challenge — making a structured past-due follow-up process a competitive necessity. For state-by-state interest rate rules on overdue invoices, the Nolo guide on charging interest covers most situations clearly.

The critical distinction: an invoice that is due soon needs a pre-due reminder. An invoice that is past due needs a follow-up email with increasing urgency. The templates below are for the latter.

Not sure how to set the right terms? See our guide to payment terms (Net 30 vs Net 15) or use the free net terms calculator.

At 7 days, assume good faith. The client likely forgot, lost the email, or their accounts payable cycle hasn't processed it yet. Keep the tone light and helpful.

This email should take 30 seconds to send. The goal is to re-surface the invoice, not to pressure. For a free tool that generates this automatically, try the payment reminder email generator.

Two weeks without payment means this isn't a simple oversight. Be direct, restate the facts, and ask for a specific response.

30 days is the inflection point. This is where you reference late fees (if your contract includes them), set a hard deadline, and document everything. For context on late fee policies, see how to charge late fees on invoices.

At this stage, log every email and response in a chase history tool. If you need to escalate later, this timestamped record becomes your evidence. See how to chase unpaid invoices for the full system.

At 60 days, the email needs to name the consequence. This isn't a reminder — it's a formal warning that you will take action.

Consider sending this by email and registered post. For formal letter versions, see overdue invoice letter templates. If a client has multiple overdue invoices, a past due statement template lets you summarise all open balances in a single document.

This is your last email before you act. Keep it short, factual, and unambiguous. No pleasantries.

After sending this, follow through. See unpaid invoice small claims court guide and how to write a demand letter.

The subject line determines whether your email gets opened. Be specific — include the invoice number, amount, and how overdue it is.

Early Stage (7–14 days)

• "Invoice #[NUM] — [X] days past due"
• "Quick follow-up: Invoice #[NUM] for $[amount]"
• "Payment reminder: Invoice #[NUM] due [date]"

Mid Stage (30 days)

• "Invoice #[NUM] — 30 days past due — action required"
• "Overdue payment: Invoice #[NUM] — please respond by [date]"

Late Stage (60–90+ days)

• "Invoice #[NUM] — 60 days past due — escalation notice"
• "FINAL NOTICE — Invoice #[NUM] — Legal action pending"
• "Urgent: $[amount] outstanding — Invoice #[NUM]"

For more subject line ideas, see 25 polite payment reminder subject lines.

1. Waiting too long to follow up. Every day you delay reduces your collection probability. The ideal first follow-up is within 1–3 days of the due date.
2. Being vague. "Just checking in on that invoice" doesn't work. State the invoice number, amount, and exactly how many days past due it is.
3. Apologizing for following up. You delivered the work. The client agreed to pay. Following up is your right, not an imposition.
4. Threatening without following through. If you say "I will refer this to collections" at 60 days and then don't do it, future warnings carry no weight. Only state consequences you intend to enforce.
5. Not keeping records. If you can't prove when you sent each reminder, you have a weaker position in any dispute or legal proceeding. Log every touchpoint.

If you've sent 4–5 past due emails over 60 days with no payment and no response, email alone won't solve this. Here's what to do next in the US:

• Phone call. A direct conversation often breaks through when emails don't. See invoice follow-up phone call scripts.
• Formal demand letter by certified mail. Many US states require a written demand before small claims filing. Sending by certified mail creates a legal record of delivery. See how to write a demand letter for an unpaid invoice.
• Small claims court. US limits vary by state — California ($12,500), Texas ($20,000), New York ($10,000), Florida ($8,000). Filing fees are typically $30–$100. No lawyer required. See unpaid invoice small claims court guide.
• Debt collection agency. Agencies charge 15–30% of the recovered amount under US contingency arrangements. Under the Fair Debt Collection Practices Act (FDCPA), agencies must follow strict rules about contact methods and times.
• Evidence pack. Before any legal step, compile your invoice, contract, delivery proof, and full chase history. InvoiceGrid generates this in one click.