How to Calculate Invoice Due Dates (With Examples)

Payment terms define the deadline for your client to pay an invoice. The term is shorthand — "Net 30" means the full invoice amount is due 30 calendar days from the invoice date. "Net" refers to the net (total) amount owed after any discounts or deductions.

The invoice date is the starting point for every calculation. This is the date printed on the invoice — not the date you sent the email, not the date the client received it, and not the date they opened it. If your invoice is dated March 1st and the terms are Net 30, the due date is March 31st regardless of when the client first sees it.

Understanding this matters because clients sometimes argue the clock should start from when they "received" the invoice. That interpretation has no legal basis in standard commercial practice. The invoice date governs the due date, full stop. If you want to avoid this argument entirely, state the exact calendar due date on the invoice alongside the payment terms.

For a deeper look at Net 30 specifically — including why it may not be the best default for freelancers — read the Net 30 payment terms guide.

Net 30

Add 30 calendar days to the invoice date.

• Invoice date: March 1st
• Due date: March 31st (March 1 + 30 days)

Net 60

Add 60 calendar days to the invoice date. Common in industries with long fulfilment cycles — construction, manufacturing, and wholesale.

• Invoice date: January 15th
• Due date: March 16th (January 15 + 60 days)

Net 90

Add 90 calendar days to the invoice date. Typically used by large enterprises and government agencies. If you're a freelancer offered Net 90, factor the wait into your pricing or require a substantial deposit.

• Invoice date: January 1st
• Due date: April 1st (January 1 + 90 days)

Net 15 and Net 7

Same logic, shorter windows. Net 15 is increasingly popular with freelancers and agencies — it halves the wait compared to Net 30, and most clients accept it without negotiation.

• Invoice date: March 10th, Net 15 → Due date: March 25th
• Invoice date: March 10th, Net 7 → Due date: March 17th

EOM (End of Month)

Payment is due on the last day of the month the invoice was issued. The actual number of days varies depending on when in the month you invoice.

• Invoice date: March 5th → Due date: March 31st (26 days)
• Invoice date: March 28th → Due date: March 31st (3 days)

Some businesses use "EOM + 30" — meaning the end of the month following the invoice month. An invoice dated March 5th on EOM + 30 terms would be due April 30th.

2/10 Net 30

The client gets a 2% discount if they pay within 10 days. Otherwise, the full amount is due in 30 days. This is a carrot-and-stick approach — reward early payment while maintaining a firm outer deadline.

• Invoice: $5,000, dated March 1st
• Pay by March 11th: $4,900 (2% discount = $100 saved)
• Pay by March 31st: $5,000 (full amount)

The 2% discount over 20 extra days annualises to approximately 36%. For clients with cash on hand, taking the discount is almost always the rational choice. For you, getting paid 20 days sooner is worth the 2% haircut.

Due on Receipt

Payment is expected immediately upon receiving the invoice. In practice, most clients treat this as 5–7 days. Best used for small amounts or established client relationships where prompt payment is the norm.

Use the free net terms calculator to compute the exact due date for any invoice date and payment term — no manual counting required.

This table shows how each payment term translates to a due date using a March 1st invoice date as a consistent example.

These errors are surprisingly common and they cost real money — either through delayed payments or weakened claims when chasing overdue invoices.

1. Counting Business Days Instead of Calendar Days

Net terms use calendar days. Always. Net 30 from a Friday doesn't skip weekends. If a client insists Net 30 means 30 business days (which would be roughly 42 calendar days), they are incorrect. Point them to any standard accounting reference or the SBA's business finance guidance — Net terms are universally understood as calendar days.

2. Using the Delivery Date Instead of the Invoice Date

The clock starts on the invoice date, not the date you delivered the work or the goods. If you delivered on March 1st but didn't invoice until March 10th, Net 30 runs from March 10th. This is why invoicing promptly matters — every day you delay sending the invoice is a day added to your wait.

3. Not Stating the Actual Due Date on the Invoice

Writing "Net 30" on an invoice is fine, but also write the specific calendar date: "Due by: March 31, 2026." This removes any ambiguity about when the client counted from and avoids the "I thought it was 30 days from when I received it" conversation. A concrete date is harder to misinterpret than a formula.

4. Forgetting Leap Years and Short Months

Net 30 from January 30th in a leap year lands on February 29th. Net 60 from December 5th crosses into February — check whether it's a 28 or 29-day month. These edge cases rarely matter, but they can cause a day or two of confusion. Using a net terms calculator eliminates the manual error entirely.

5. Mixing Up EOM With Net 30

An invoice dated March 5th on EOM terms is due March 31st (26 days). The same invoice on Net 30 is due April 4th (30 days). An invoice dated March 28th on EOM terms is due March 31st (3 days). On Net 30, it's due April 27th (30 days). EOM and Net 30 only produce the same result if the invoice is dated exactly 30 days before month-end.

If an invoice has no payment terms, you're relying on local statutory defaults — and that's a weak position. Here's what the law says:

• England and Wales: The Late Payment of Commercial Debts (Interest) Act 1998 sets a statutory 30-day payment period and allows you to charge interest (8% + Bank of England base rate) on late payments.
• United States: No federal statute sets a default payment period. Courts generally consider 30 days a reasonable expectation, but it varies by state and industry. Without explicit terms, you have less leverage in collections.
• EU: The Late Payment Directive sets a 30-day default for business-to-business transactions and 60 days for public authorities.

The fix is simple: always state your terms. Put them in your contract, on your invoice, and in the email accompanying the invoice. Three places, same terms, no ambiguity. If a client has their own purchase order process that dictates different terms, negotiate before starting work — not after the invoice is issued.

For guidance on structuring payment terms in freelance agreements specifically, see the freelance contract payment terms guide.

Calculating the due date is step one. Getting paid by that date is step two. Here's what works in practice:

State the Due Date Explicitly

Every invoice should show both the payment term ("Net 30") and the specific calendar date ("Due by: April 4, 2026"). A concrete date creates a concrete expectation. Vague terms create vague deadlines.

Send a Reminder Before the Due Date

A brief email 3–5 days before the due date — "Just a reminder that invoice #1042 for $3,500 is due on April 4th" — prevents the "I forgot" excuse. Most late payments are oversight, not intent. A polite nudge before the deadline recovers more invoices than a firm demand after it.

Follow Up Immediately When Overdue

If payment doesn't arrive on the due date, follow up the next business day. Waiting a week "to be polite" signals that your due dates are suggestions. A prompt, professional follow-up the day after shows that you track your invoices and expect timely payment.

Include a Late Fee Clause

A late fee clause in your contract (typically 1.5% monthly on overdue balances) creates a financial cost to paying late. Even clients who never actually get charged the fee tend to pay faster when they know it exists. The clause must be agreed to in the contract — adding it to an invoice after the fact isn't enforceable.

Track Every Invoice Systematically

You can't chase what you don't track. If you're managing invoices in a spreadsheet, it's easy for due dates to slip past unnoticed — especially when you're focused on client work. InvoiceGrid shows every outstanding invoice on a visual Kanban board with automatic overdue flags, so you always know which invoices need attention today.