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Count the time between two dates, or add and subtract years, months, weeks and days from a date.
Years and months are applied first, then weeks and days.
Total days is the exact number of days from the start to the end. The end date itself is not counted, so Monday to Friday of the same week is four days. Years, months and days expresses the same span in calendar units: the largest number of whole months that fit between the two dates, and then the days that are left over.
Working days counts the Mondays to Fridays in that range, again without the end date. Public holidays are different in every country and region, so they are not subtracted.
Months have different lengths, so adding a month needs a rule for dates that do not exist in the month reached. This tool keeps the day of the month when it can and otherwise stops at the last day of the month: 31 January plus one month is 28 February, or 29 February in a leap year. The page tells you whenever this rule was applied.
One consequence is that month arithmetic cannot always be undone. 31 January plus one month is 28 February, but 28 February minus one month is 28 January. For the same reason the order of the steps matters: years and months are applied first, as a single step, and weeks and days are added afterwards.
A year is a leap year when it is divisible by 4, except for century years, which must be divisible by 400. So 2000 had a 29 February and 1900 did not.
A local day is not always 24 hours long. On the days when clocks change for daylight saving time it is usually 23 or 25 hours long, and a calculation that subtracts two local timestamps and divides by 24 hours can come out one day short. This tool does all its arithmetic on calendar dates in UTC, which JavaScript counts as exactly 24 hours each, so a clock change never affects the result. A time you enter is treated as a plain clock reading without a time zone.
The week number follows ISO 8601: weeks start on Monday, and week 1 is the week that contains the first Thursday of the year. The first days of January can therefore belong to the last week of the previous year. For example, 1 January 2027 is in week 53 of 2026.
No. The count runs from the start date up to, but not including, the end date, so from 1 March to 2 March is one day. If you need both dates counted, add one to the total.
February has no 31st, so the result stops at the last day of the month. In a leap year it is 29 February. PostgreSQL, MySQL and Java's java.time apply the same rule when a day does not exist in the month reached.
No. Working days are the Mondays to Fridays in the range. Public holidays depend on the country, the region and the year, so subtract the ones that apply to you.
No. The calculation is done by JavaScript in your browser tab, and the dates are not stored. Only your choice between the two calculation modes is remembered in this browser.