---
title: "Due Date Calculator | Numequo"
description: "Add calendar, business or working days to calculate a due date. Get a clear result with the formula, examples and useful explanations."
canonical: "https://www.numequo.com/time/dates-calendar/due-date-calculator/"
locale: "en"
---
[Numequo](https://www.numequo.com/) › [Time](https://www.numequo.com/time/) › [Dates and calendar](https://www.numequo.com/time/dates-calendar/)

# Due Date Calculator

Choose how days must be counted and optionally exclude specific holidays.

## Input data

- **Starting date** - type: date; default: 2026-08-12
- **Days to add** - type: number; default: 30; min: 0; max: 10000; step: 1
- **Day type** - type: choice; default: calendar; options: Calendar days, Business days (Mon–Fri), Working days (Mon–Sat)
- **Excluded holidays** - type: text; Optional dates separated by commas: 2026-01-01, 2026-12-25

## How it works

Calendar days include every date. Business days exclude Saturday and Sunday. Working days exclude Sunday. Entered holidays are excluded from both work-based modes.

## Quick examples

- **30 calendar days** - Starting date: 2026-08-12, Days to add: 30, Day type: calendar, Excluded holidays: 
- **10 business days** - Starting date: 2026-08-12, Days to add: 10, Day type: business, Excluded holidays: 
- **5 working days with a holiday** - Starting date: 2026-12-21, Days to add: 5, Day type: workable, Excluded holidays: 2026-12-25

## Understanding your result

The starting date is day zero. The result is reached after counting the requested number of eligible days.

Last verified: 29 September 2026 (2026-09-29)

## Frequently asked questions

### Is the starting date day one?

No. Counting begins on the following eligible date.

### What is the difference between business and working days?

Here, business days are Monday to Friday and working days are Monday to Saturday.

### Are national holidays automatic?

No. Add the dates relevant to your location and situation.

## Related calculators

- [Business Days Calculator](https://www.numequo.com/time/dates-calendar/business-days-calculator/) - Count business days between two dates with configurable weekends and holidays.
- [Date Add or Subtract Calculator](https://www.numequo.com/time/dates-calendar/date-add-subtract-calculator/) - Add or subtract days, weeks, months or years from any calendar date.
- [Date Countdown Calculator](https://www.numequo.com/time/dates-calendar/date-countdown-calculator/) - Count the days remaining from today until a chosen date.
- [Age Calculator](https://www.numequo.com/time/dates-calendar/age-calculator/) - Calculate an exact age between two dates.
- [Date Difference Calculator](https://www.numequo.com/time/dates-calendar/date-difference-calculator/) - Count days and weeks between any two dates.
- [ISO Week Number Calculator](https://www.numequo.com/time/dates-calendar/iso-week-number-calculator/) - Find the ISO week number and week-based year for any date.

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