Date Difference Calculator
Find the number of days, weeks, months and years between any two dates.
- As years / months / days
- 0y 0m 0d
- Total weeks (approx.)
- 0.0
This calculator provides estimates only, for general information and entertainment purposes. It isn't professional advice — confirm anything important independently before relying on it.
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How this calculator works
Pick a start date and an end date to find exactly how many days apart they are — useful for deadlines, countdowns, project timelines, or working out how long something lasted.
The result shows the total day count, plus the same span broken into whole years, months and days for a more intuitive read on longer gaps. If the end date is before the start date, they're swapped automatically so the difference is always shown as a positive span.
Worked example: from 1 March to 15 June is 106 days total, or 3 months and 14 days in calendar terms — the two figures can look inconsistent at a glance because months have different lengths, but both describe the same span. The calendar breakdown counts a full month only once the same day-of-month has passed, so 1 March to 1 April is exactly "1 month, 0 days", while 1 March to 30 April is "1 month, 29 days" rather than rounding up to two months.
This is commonly used in Australia for things a simple mental count gets wrong: working out notice periods and lease end dates, checking how many days until a visa or licence expires, calculating leave entitlements, or figuring out a contract's exact term length. It's also useful for finance — many interest and penalty calculations are done on an exact day-count basis, not a rounded month count.
A common source of confusion is leap years: February has 29 days in a leap year (any year divisible by 4, except century years not divisible by 400), which shifts day counts spanning that February by one day compared to a non-leap year — this calculator accounts for that automatically using each date's real calendar, so you don't need to track leap years manually.
Frequently asked questions
- Does this count the start and end day?
- The day count is the number of days between the two dates (end minus start) — for example, 1 January to 3 January is 2 days apart, not 3.
- Can I use this to count down to a future date?
- Yes — set the start date to today and the end date to the date you're counting down to, and the total days figure is your countdown.
- Why does the years/months/days breakdown look different from dividing the total days by 30?
- Because months aren't all 30 days — they range from 28 to 31 — so dividing total days by 30 gives a rough approximation, while the calendar breakdown counts actual elapsed months and years against the real calendar, which is more accurate for anything longer than a few weeks.
- Does this handle leap years correctly?
- Yes — the day count is based on each date's actual position on the calendar, including the extra day in February during a leap year, so spans crossing a 29 February are calculated correctly without any manual adjustment.