Days Between Dates Calculator
Calculate the number of days between two dates instantly. This free tool also shows weeks, approximate months and years between any two dates.
About this tool
How many days until the wedding, the exam, the product launch or the visa expiry? Counting days between two dates by hand is tedious, and month boundaries make it error-prone. Most people just want the number without the calendar gymnastics.
Our free days-between-dates calculator gives you the exact day count instantly. Pick the two dates and the tool also breaks the gap into weeks, approximate months and years, which is useful for planning timelines and contracts.
How to use
Choose the start date and the end date with the date pickers, then press Calculate Difference. The tool shows total days first, then the same span expressed as weeks, months and years.
The order does not matter: picking the later date first still gives the same positive difference. Leap years are counted correctly in the day total.
The math behind it
The tool converts each date to its millisecond timestamp and takes the absolute difference, then divides by 86,400,000, the number of milliseconds in a day. Weeks are days divided by 7. Months use the average month length of 30.44 days, and years use 365.25 days to account for leap years.
The day count itself is exact; only the month and year rows are labeled approximate, because real months and years vary in length.