Date add and subtract calculator

Move a date forward or backward by one unit at a time, including clamped month and year shifts.

What this calculator covers

Use this date add/subtract calculator when the request is simple: one amount, one unit, one direction. It is a faster fit than a mixed-unit date tool when the only question is something like plus 10 days or minus 2 months.

Days and weeks move by fixed day counts, while months and years follow calendar clamping so month-end dates stay valid after the shift.

Frequently asked questions

What happens when I add one month to January 31?
The result clamps to the last valid day of February, which is either February 28 or February 29 depending on the year. The tool makes this clamping rule explicit so you can see the adjusted date clearly.
Can I subtract more days than are in a year?
Yes. There is no upper limit on the amount you can add or subtract in the days or weeks units.
What is the difference between this tool and the date calculator?
This tool handles a single unit at a time, such as adding 14 days or subtracting 3 months. The date calculator lets you combine years, months, weeks, and days in one request.
Does the calculator accept decimal amounts?
No. Only whole numbers are accepted. Entering a fractional amount will return an error.

Tool

Run the calculation

Result

RESULT · DATE SHIFT

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Subtract 1 year from Feb 29, 2024 to land on Feb 28, 2023.

Base date
Feb 29, 2024
Adjustment
Subtract 1 year
Result date
Feb 28, 2023
Elapsed day change
366 days

Step-by-step solution

  1. 1.Start from Feb 29, 2024 as the anchor date.
  2. 2.Apply the single-unit move as subtract 1 year using the selected unit's calendar rule.
  3. 3.Read the resulting calendar date as Feb 28, 2023, which is 366 days from the anchor date.

Walkthrough

Visual walkthrough

The simple add/subtract form keeps one date, one amount, and one unit in view.

  1. 01

    Set the anchor date

    Feb 29, 2024

    Everything starts from the chosen base date.

  2. 02

    Apply the single-unit move

    Subtract 1 year

    Days and weeks move by fixed day counts; months and years clamp to the last valid day when needed.

  3. 03

    Read the result

    Feb 28, 2023

    The move changes the calendar by 366 elapsed days overall.

    Feb 28, 2023