Date duration calculator
Work out the exact duration between two dates in years, months, and days, plus the total number of days, or add days, months, and years to a date, or subtract them from it. Both the Gregorian and the Hijri (Umm al-Qura) calendars are supported. Everything is computed in your browser.
To calculate the duration between two dates, enter both dates in the Gregorian or the Hijri calendar and the difference appears in years, months, and days with the total day count. To add or subtract time from a date, enter the base date and the amounts. It is free, needs no sign-up, and your dates never leave your browser.
How to use it
Choose what you need: a duration between two dates, or an addition or subtraction on one date. For a duration, enter the start date and the end date in the Gregorian or the Hijri calendar, and the difference appears in years, months, and days with the total day count. For an addition or subtraction, enter the base date and the amounts of years, months, and days, and the resulting date appears with its equivalent in the other calendar.
When it helps
Contract periods, notice periods, project timelines, and waiting periods all need an exact date difference, and counting by hand breaks on leap years and unequal months. The Hijri side runs on the official Umm al-Qura table, where every month length is fixed day by day, not guessed as 29 and 30 in alternation.
Common questions
How is the duration counted?
The tool counts whole years first, then whole months, then the remaining days, using the real length of every month it crosses. A 29-day February in a common year and a 30-day month on the Hijri table are both counted exactly.
Which Hijri calendar is used?
The Umm al-Qura calendar, the official civil calendar of Saudi Arabia, on the same table official systems use. The supported range is 1318 to 1500 AH.
What happens when the result month does not have the day I started from?
The day is pinned to the last day of that month. For example, 31 January plus one month is 28 February, or 29 February in a leap year, and the same rule applies to Hijri month lengths.
Are my dates sent anywhere?
No. Every calculation happens entirely in your browser. Your dates are never uploaded, stored, or shared.
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