Browse categories

Date Calculator

Find a past or future calendar date by adding or subtracting whole days.

ResultSaturday, 31 January 2026 · +30 days.The resulting calendar date accounts for month lengths and leap years.

Calculations happen locally in your browser.

How to use this calculator

  1. Choose a valid starting date, an operation, and a whole number of days.
  2. Review the live result and use Copy result when you need to share it.

How the calculation works

The calculation uses UTC calendar arithmetic, so month lengths, year boundaries, and leap days are handled without daylight-saving shifts.

Formula

Result date = starting date ± whole calendar days

Step-by-step calculation

  1. Choose a valid starting date, an operation, and a whole number of days.
  2. The calculation uses UTC calendar arithmetic, so month lengths, year boundaries, and leap days are handled without daylight-saving shifts.
  3. Check the displayed result, then copy it if needed.

Worked example

Adding one day to 28 February 2024 produces 29 February 2024.

Risk guidance

Frequently asked questions

Are weekends included?

Yes. This calculator adds or subtracts calendar days, including weekends and public holidays.

Does this tool send my inputs anywhere?

No. The interactive calculation runs in your browser and this site does not submit tool inputs to a backend.

How should I use the result?

Check that the entered units and values match your situation, especially around dates, breaks, and rounding.

Related tools