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Date calculator

Date math

Deadlines and day counts without a spreadsheet.

Runs in your browser. Numbers stay on this device — nothing is uploaded to BrowserSpaces for processing.

Add / subtract

Shift a date by N days.

Difference

Days between two dates.

ISO friendly

Clear date inputs.

Use the calculator

Days

217

Weeks

31

Hours

5208

How it works

How date math works

Differences use UTC day boundaries from the date parts you enter. Add/subtract moves by whole days.

Three steps

  1. 1

    Choose mode

    Shift or difference.

  2. 2

    Enter dates

    And day count if shifting.

  3. 3

    Get result

    New date or day span.