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.
Date math runs locally in your browser.
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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
Frequently asked questions
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Last reviewed: 2026-09-18