Calculate the number of calendar days between two dates.
The calculator measures the elapsed calendar days between midnight at the start of each selected date. The result is an absolute difference, so reversing the dates gives the same number.
A date difference measures elapsed calendar time between two dates. The result can be expressed in days, while the interpretation of an interval may depend on whether the start or end date is counted as part of the period.
If a project starts on April 1 and ends on April 10, the elapsed difference is 9 days when measuring the time from the start date to the end date. If a business counts both calendar dates as working days or inclusive days, that is a different convention.
Do not confuse elapsed days with inclusive day counts. Month lengths and leap years also mean that a month is not always the same number of days. For contracts, billing, or deadlines, follow the counting convention specified by the relevant document.
The Age Calculator uses dates differently because age is based on completed birthdays. The Time Duration Calculator is more appropriate when you already have clock times such as 09:30 and 14:45.