Are payment terms in calendar or working days?

Calendar days by default. If you mean working days, state that explicitly in your terms.

Does the count start on the invoice date or the delivery date?

Usually the invoice issue date. Some contracts start it on delivery or on receipt of the invoice, so check which applies.

What happens if the due date falls on a weekend?

Most businesses accept payment on the next working day. Say so in your terms if you want it to be unambiguous.

What does "30 days end of month" mean?

Thirty days after the end of the month in which the invoice was issued — considerably longer than Net 30 for an invoice sent early in a month.

Can I set a due date shorter than my usual terms?

Yes, if the client has agreed to it. Changing terms only on the invoice, without agreement, is weak ground if the payment is disputed.

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Invoice Due Date Calculator

Pick an issue date and a payment term to get the exact due date, written out in full so you can put it straight onto the invoice.

Calculate an invoice due date

Invoice issue date

Payment term (days)

Payment due

Thursday, 22 October 2026

2026-10-22 — 30 calendar days after the issue date.

Put this exact date on the invoice alongside the term. A date is a deadline; a term is only a policy.

Put the due date on an invoice

Create the invoice, set this date, and download the PDF.

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How do you work out an invoice due date?

Add the number of days in your payment term to the invoice issue date. Net 30 issued on 1 October is due on 31 October; Net 15 issued the same day is due on 16 October.

The days are calendar days, not working days, unless your contract says otherwise. Where a due date lands on a weekend or public holiday, most businesses treat the next working day as acceptable — but say so in your terms rather than assuming it.

What is Net 30?

Net 30 means the full invoice amount is payable within 30 days of the invoice date. Net 7, Net 14, Net 15, Net 45 and Net 60 work the same way with their respective day counts.

Be careful with customers who operate end-of-month terms — "30 days end of month" means 30 days after the month closes, which for an invoice issued on the 2nd can be nearly 60 days.

Common terms and what they produce

Term	Days added	Issued 1 October 2026 → due
Due on receipt	0	1 October 2026
Net 7	7	8 October 2026
Net 14	14	15 October 2026
Net 15	15	16 October 2026
Net 30	30	31 October 2026
Net 45	45	15 November 2026
Net 60	60	30 November 2026
Net 90	90	30 December 2026

Put the date on the invoice, not just the term

"Net 30" is a policy; "Due 31 October 2026" is a deadline. An approver scanning an invoice will act on a date and ignore a term, and a payment run scheduled by date is the one you get paid in. Show both: the term explains the arrangement, the date sets the expectation.

If you charge late interest, the due date is also the day it starts accruing, so an ambiguous due date makes any late fee harder to justify.

Choosing a term that gets paid

Align the term with how the customer actually pays. A company with two payment runs a month will not honour Net 7 no matter what the invoice says, and a term that is structurally impossible to meet just turns every invoice into a late one. Ask about their cycle and set terms that land inside it — then hold them to the date.

Frequently asked questions

Published 18 September 2026. Last updated 18 September 2026. Written by the Free Invoice Generator team. General invoicing information, not tax or legal advice.

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