Days Between Dates

What this tool does

This tool answers two related questions about dates: how much time falls between two dates (in total days, weeks, and a calendar-accurate years/months/days breakdown), and what date results from adding or subtracting a number of days to a starting date. Both update live as you pick dates, calculated locally in your browser using calendar-aware math that correctly handles varying month lengths and leap years.

Example use case

Planning around a deadline 45 days from today, checking how many days remain until an event, or figuring out exactly how many weeks a project spanned between its start and end dates are all common scheduling questions that are easy to get wrong counting on a calendar by hand, especially across month or year boundaries.

Inclusive vs. exclusive counting

This tool counts the number of full days between two dates — for example, from January 1 to January 3 is 2 days. If you need an "inclusive" count that also counts the start date itself (3 days in that example), add 1 to the total days result.