---
title: "Date Add or Subtract Calculator | Numequo"
description: "Add or subtract days, weeks, months or years from any calendar date. Get a clear result with the formula, examples and useful explanations."
canonical: "https://www.numequo.com/time/dates-calendar/date-add-subtract-calculator/"
locale: "en"
---
[Numequo](https://www.numequo.com/) › [Time](https://www.numequo.com/time/) › [Dates and calendar](https://www.numequo.com/time/dates-calendar/)

# Date Add or Subtract Calculator

Choose a date, an operation and a calendar unit to find the resulting date.

## Input data

- **Starting date** - type: date; default: 2026-08-12
- **Operation** - type: choice; default: add; options: Add, Subtract
- **Amount** - type: number; default: 30; min: 0; max: 100000; step: 1
- **Unit** - type: choice; default: days; options: Days, Weeks, Months, Years

## How it works

Days and weeks are shifted as exact calendar days. Months and years preserve the day number when it exists, otherwise the last valid day is used.

## Quick examples

- **Add 30 days** - Starting date: 2026-08-12, Operation: add, Amount: 30, Unit: days
- **Subtract 3 months** - Starting date: 2026-08-12, Operation: subtract, Amount: 3, Unit: months
- **Add 1 year to leap day** - Starting date: 2024-02-29, Operation: add, Amount: 1, Unit: years

## Understanding your result

The result is the calendar date reached after applying the selected interval. Weekends and holidays are included.

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

## Frequently asked questions

### Are weekends included?

Yes. This calculator uses calendar intervals.

### What happens to 31 January plus one month?

The result is the last valid day of February.

### Can I subtract a period?

Yes. Select Subtract and enter a positive amount.

## Related calculators

- [Due Date Calculator](https://www.numequo.com/time/dates-calendar/due-date-calculator/) - Add calendar, business or working days to calculate a due date.
- [Date Difference Calculator](https://www.numequo.com/time/dates-calendar/date-difference-calculator/) - Count days and weeks between any two dates.
- [Business Days Calculator](https://www.numequo.com/time/dates-calendar/business-days-calculator/) - Count business days between two dates with configurable weekends and holidays.
- [Age Calculator](https://www.numequo.com/time/dates-calendar/age-calculator/) - Calculate an exact age between 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.
- [Day of the Week Calculator](https://www.numequo.com/time/dates-calendar/day-of-week-calculator/) - Find which weekday corresponds to any valid calendar date.

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