Date Calculator
Count the days between two dates, or add and subtract days from any date.
Date math runs locally in your browser.
What is date calculator?
Two date utilities in one: the gap between any two dates (in days, with week/month/year equivalents), and a date shifter that adds or subtracts a number of days — useful for deadlines, due dates, and countdowns.
All math respects real calendar dates, including month lengths and leap years, and uses your local timezone so a date you pick is the date you mean.
How to use it
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Difference
Pick From and To dates to see the gap in days and equivalents.
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Shift a date
Pick a starting date and a day offset; negative values go backwards.
Examples
January gap
From 1 Jan to 31 Jan.
2026-01-01 → 2026-01-31
Result: 30 days
Due date
30 days after 30 Jan 2026 crosses the month boundary.
2026-01-30 + 5
Result: Wed, Feb 4, 2026