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All calculatorsMethodology

Invoice Due Date Calculator

Add net payment terms to an invoice date using calendar days, with an explicit optional weekend adjustment and no hidden holidays.

Interactive calculator · Method INVOICEDUE-1.1 · Last reviewed: 2026-10-05

Calculate your scenario

Unadjusted due date = invoice date + entered calendar days; the invoice date is day zero. Optional weekend adjustment moves only Saturday or Sunday forward to Monday or backward to Friday. Calendar arithmetic uses UTC day boundaries to avoid daylight-saving shifts.

Your inputs

Try an example

Default worked example. Edit the inputs to calculate your scenario.

Default worked example

Adjusted due date 2026-12-04
Unadjusted calendar due date 2026-12-04
Net terms 60 calendar days
Weekend shift 0 days

2026-10-05 + 60 calendar days = 2026-12-04. The selected weekend policy shifts this by 0 days to 2026-12-04. No bank holidays are processed.

How to use the calculator

Enter the invoice date and net terms in calendar days. Choose whether a weekend due date stays unchanged or moves to the previous or next weekday. Check both original and adjusted dates.

What the result means

Net 60 on 2026-10-05 produces 2026-12-04. The weekend policy is an entered agreement, not a legal rule.

Formula and units

Unadjusted due date = invoice date + entered calendar days; the invoice date is day zero. Optional weekend adjustment moves only Saturday or Sunday forward to Monday or backward to Friday. Calendar arithmetic uses UTC day boundaries to avoid daylight-saving shifts.

Worked examples

Net 60 from October 5: Invoice date: 2026-10-05 YYYY-MM-DD calendar date; Net payment terms: 60 calendar days; Weekend policy: none.
Example result: Adjusted due date: 2026-12-04; Unadjusted calendar due date: 2026-12-04; Net terms: 60 calendar days; Weekend shift: 0 days.

Leap-year net 30: Invoice date: 2028-02-01 YYYY-MM-DD calendar date; Net payment terms: 30 calendar days; Weekend policy: forward.
Example result: Adjusted due date: 2028-03-02; Unadjusted calendar due date: 2028-03-02; Net terms: 30 calendar days; Weekend shift: 0 days.

Limitations and common mistakes

Contract terms determine the actual due date. This does not interpret business-day clauses, jurisdiction rules, bank holidays, receipt dates or grace periods. Backward adjustment can move a net-zero due date before the invoice date; that is shown explicitly.

Net 60 means adding sixty calendar days in this model, not two calendar months. Weekend adjustment does not implement public holidays or contractual/legal payment rules.

Sources and assumptions

Method INVOICEDUE-1.1; last formula review 2026-10-05. Sources and their supported claims. Calculation methodology.