Date Calculator

Calculate the difference between two dates or add and subtract days, weeks, months, and years from any date. Free online tool.

How It Works

  1. Choose an operation: add or subtract days from a date, or find the difference between two dates.
  2. Enter your start date (and end date for difference calculation).
  3. Enter the number of days, weeks, or months to add or subtract.
  4. The result date or day count appears instantly.

Formula

Add days:        Result = Start Date + N days
Subtract days:   Result = Start Date − N days
Difference:      Days = End Date − Start Date

Example

Input: Start: 1 January 2026, add 100 days
Result: Result: 11 April 2026

FAQ

Yes — you can add or subtract days, weeks, or months from any date.

Yes — leap years and varying month lengths are handled automatically.

No. All calculations run entirely in your browser. No data is sent to or stored on our servers.

Yes — select the difference mode, enter both dates, and the exact number of days is shown instantly.