Date Difference Calculator

Enter a start date and an end date. The calculator subtracts the start moment from the end moment. When you leave both times blank, both moments are midnight, so the result is a whole number of calendar days.

January 1, 2026, to February 1, 2026, is 31 days. If the start is later than the end, the result is negative. Dates use the month/day/year reading common in the United States; the picker also stores ISO YYYY-MM-DD.

Count the span

End minus start

Enter both dates.

Date questions

Is January 1 to February 1 thirty-one days?

Yes, when both times are blank. The calculator uses midnight on each date and subtracts start from end.

What if I only care about the dates and not the hours?

Leave both time fields empty. The leftover-hour line appears only after you enter a time.

What does a negative result mean?

The start moment is later than the end moment. The number is still end minus start, with a minus sign.