Date Calculators

Work out what date it was, what date it will be, and how much time sits between any two dates. 31 free tools, all running in your browser.

    Most used

    The six date tools people open most often.

    Days Ago Calculator The exact date a given number of days ago. Open Days Since Calculator How many days have passed since a date. Open Days Until Calculator How many days remain until a date. Open Date Difference Calculator Days, weeks, months and years between two dates. Open Years Ago Calculator The exact date a given number of years ago. Open Age Calculator Exact age in years, months and days. Open

    Relative date calculators

    Start from a number of days, weeks, months or years and get the exact calendar date.

    Days Ago Calculator Weeks Ago Calculator Months Ago Calculator Years Ago Calculator Hours Ago Calculator

    Since and until

    Start from a date and get the number of days that have passed, or that remain.

    Days Since Calculator Days Until Calculator

    Between two dates

    Measure the gap between any two dates in days, working days, or years and months.

    Age Difference Calculator Days Until Birthday Calculator Date Difference Calculator Age Calculator Between Two Dates Age Calculator Business Days Calculator Day of the Week Calculator Leap Year Calculator ISO Week Calculator Day of Year Calculator Weeks Between Dates Calculator Months Between Dates Calculator Years Between Dates Calculator

    Date planning

    Move forward or backward from a date, and work out hours from a shift.

    Weeks From Now Calculator Months From Now Calculator Years From Now Calculator Hours From Now Calculator Minutes From Now Calculator Days From Today Calculator Work Hours Calculator Time Zone Converter Christmas 2026 Countdown Countdown Timer Unix Timestamp Converter

    Choosing the right date calculator

    Date questions fall into a few shapes, and picking the matching tool saves a lot of second-guessing.

    You know the number, you want the date

    If the question sounds like "what date was 90 days ago" or "what date is 45 days from now", you want a relative date tool. Enter the number and read off the date. Use the days, weeks, months or years version depending on the unit the question came in, because they are not interchangeable: four weeks is exactly 28 days, while one month is anywhere from 28 to 31.

    You know the date, you want the number

    If the question sounds like "how long since I started" or "how many days until the deadline", you want Days Since or Days Until. These take a calendar date and count the days between it and today.

    You know both dates

    If you have a start and an end and need the span between them, use the Date Difference Calculator. It reports the gap in days, and also breaks it into years, months and days, which is the form contracts and age calculations usually want. When weekends should not count, use the Business Days Calculator instead.

    Calendar days or working days

    Calendar days count every day, including weekends and public holidays. Working days skip Saturdays and Sundays. Legal and statutory deadlines are usually written in calendar days, while internal turnaround times are usually quoted in working days. Check which one applies before relying on a figure, because over a month the two differ by roughly nine days.

    A note on accuracy

    Every tool here uses local midnight for date arithmetic, so results do not drift when your time zone crosses a day boundary. Month and year arithmetic clamps to the end of the target month, meaning March 31 minus one month gives February 28 or 29 rather than an invalid date. This matches the convention used by ISO 8601 and by most billing and contract systems.

    Date calculation questions

    They start from opposite ends. "Days ago" takes a number and returns a date: you know it was 90 days, you want to know the date. "Days since" takes a date and returns a number: you know the date, you want to know how long it has been. The same pair exists in the other direction, where "days until" counts forward to a date you name.
    Use the unit the original requirement was written in, because they are not interchangeable. Four weeks is always exactly 28 days, while a calendar month is 28 to 31 days. A "30 day" return window and a "one month" return window can end on different dates, and over a year the gap compounds: 52 weeks is 364 days, one day short of a year.
    Every tool counts calendar days, including weekends and public holidays, except the Business Days Calculator, which skips Saturdays and Sundays. Statutory and contractual deadlines are usually written in calendar days; internal turnaround times are usually quoted in working days. Over a month the two differ by roughly nine days, so it is worth checking which one applies before relying on a figure.
    No. The tools report elapsed days by default, which excludes the start date and includes the end date. January 1 to January 3 is two elapsed days. Some legal wording counts both ends, giving three, so the Date Difference Calculator offers an inclusive option and labels which convention is in use.
    February 29 exists only in leap years: years divisible by 4, except century years, which must also be divisible by 400. So 2000 was a leap year and 1900 was not. Subtracting a year from February 29 clamps to February 28, which is the convention used for legal age and contract anniversaries.
    The tools use the Gregorian calendar throughout. Countries adopted it at different points between 1582 and 1927, so a span crossing a country's adoption date may not match historical records for that country. For any date in living memory the results are exact.