Find the days, weeks, months, and years between two dates, or add/subtract time from a date.
The "Days Between Two Dates" tool breaks the gap into whole years, months, and days the same way our Age Calculator does — anchored to the day-of-month of the start date, so a month is only "complete" once that anchor day is reached again. The calendar-day total is a straight count of days between the two dates, unaffected by that breakdown.
By default, the gap between Jan 1 and Jan 2 is counted as 1 day — the number of nights, essentially. Checking "include end day" instead counts both endpoints, which is useful for things like "how many days does this rental cover" where both the check-in and check-out day count.
Yes — adding, say, 1 month to Jan 31 lands on the correct date even when the target month is shorter, following standard calendar rollover rules.
Yes — switch the operation to "Subtract" in the second tool to count backward from the start date.
Pick another tool to jump straight to it.