Date Difference Calculator
Calculate the number of days, weeks, months, and years between two dates.
Guide
How it works
The date difference calculator measures the span between any two calendar dates and expresses it in several units at once: years, months, weeks, days, hours, and minutes. Pick a start date and an end date, and it returns the full duration between them, handling the awkward parts of the calendar - leap years, months of different lengths, and the shift across year boundaries - for you. It works equally well for dates in the past and the future, so you can measure how long ago something happened or how far away an upcoming date is.
How it works
Under the hood, the tool converts each date to a point in time, finds the absolute gap between them in milliseconds, and then divides that gap into the units you see. Days are the exact count of whole days between the two dates. Weeks are that day count divided by seven. Hours and minutes are simply the day count multiplied out, which is why a one-day difference shows as 24 hours and 1,440 minutes. Because the result is an absolute value, the order you enter the dates in does not change the answer; the gap between March and June is the same whichever you put first.
Why months and years are approximate
Days, hours, and minutes are exact, but months and years need a convention, because real months range from 28 to 31 days and a year is not a whole number of weeks. This calculator uses the common averages of about 30.44 days per month and 365.25 days per year, which keeps long spans accurate on average while staying simple. For a span of a few months that figure may differ slightly from a strict calendar count, so when you need the exact number of whole calendar months - for a contract term or a notice period, say - rely on the day count, which is always precise, rather than the rounded month figure.
A worked example
Take a start date of 1 January 2025 and an end date of 31 December 2025. The calculator counts 364 whole days between them, which it also reports as 52 weeks, roughly 11 months, and about 1 year. In hours that is 8,736, and in minutes 524,160. If you instead measured 1 January 2024 to 1 January 2025, the count would be 366 days, because 2024 is a leap year and includes 29 February. That single extra day is exactly the kind of detail the calculator handles so you do not have to.
Common uses
- Counting down to a deadline, holiday, wedding, or trip, or measuring how long since a past event.
- Working out the length of a lease, employment period, loan term, or notice period in days.
- Tracking a project duration or the gap between two milestones.
- Checking how many days you have held an investment or stayed somewhere for tax or visa purposes.
When precise legal or financial timing matters, confirm the figure against the exact terms of your agreement or with the relevant authority, since some rules count days inclusively or exclude weekends and public holidays.
Does this calculator include both the start and end dates?expand_more
It counts the number of complete days between the two dates, which effectively excludes the start date and includes the end date. If you need an inclusive count - for example, counting both the first and last day of an event - add one to the day result.
Does it account for leap years?expand_more
Yes. Because the calculation works from the actual calendar timestamps of each date, any 29 February that falls between your two dates is automatically included in the day count, so leap years are handled correctly.
Why does the months figure look slightly off?expand_more
Months vary from 28 to 31 days, so the calculator uses an average of about 30.44 days per month to convert. Over long spans this is accurate, but for a few months it can differ from a strict calendar count. Use the exact day figure when you need precision.
Can I measure the difference to a date in the future?expand_more
Yes. The end date can be in the past or the future. The result is shown as an absolute duration, so the order of the dates does not change the answer.
Does the result include hours and minutes of a partial day?expand_more
This calculator works at the level of whole days, then expresses that span in larger and smaller units. For a live, second-by-second countdown to a specific date and time, use the Countdown Calculator instead.
Next steps