Invoice Due Date Calculator

How it works

Payment terms on an invoice specify how long the client has to pay. Common terms are Net 30 (30 days), Net 60, or immediate payment. This calculator takes the invoice date and adds the number of days in the payment terms to show the exact due date.

It is a simple calendar-day calculator — the result is the invoice date plus the term days, including weekends. If your payment process only counts working days, use the Deadline Calculator instead, which allows you to skip weekends.

Common payment terms explained:

• Immediate: payment due right away — usually before goods are dispatched or services begin
• Net 30 / Net 60 / Net 90: the number is the calendar days from the invoice date by which payment is expected
• Custom: any number of days specific to your agreement

Small business use: many small businesses offer Net 30 as standard, but chasing late payments is time-consuming. Embedding this calculator on your invoice guidance page helps clients understand exactly when payment is due, reducing ambiguity and late queries.

Note: this calculator adds calendar days, not business days. If an invoice dated 1st March with Net 30 is due on 31st March, that's 30 calendar days. If you need to exclude weekends and holidays, use the Deadline Calculator.

How to add it