Is the end date included in the count?

The day count is the nights between the two dates: Monday to the next Monday is 7, and 1 September to 30 September is 29. If you want both dates counted, add one. The weekday and weekend-day rows do count both dates, because "how many working days in September" means the 1st through the 30th, and the label under each figure says which convention it uses.

How are the months worked out?

Whole calendar months first, by the same rule as adding a month: 31 January to 28 February is one month and no days, because 31 January plus one month is 28 February. Whatever is left after the last whole month is shown as days. Dividing by an average month length of 30.44 days is where most calculators go wrong.

What if the end date is before the start?

The span is counted backwards and the page says so. Swap the two dates if you would rather read it the other way round.

Does daylight saving change the answer?

No. Both dates are calendar dates, not clock times, so a day stays a day across a clock change. For hours and minutes between two moments on a clock, use the duration calculator.

Days Between Two Dates

Count the days between two dates, then see the same span as weeks and days, as whole months and days, and as weekdays and weekend days, with the day of the week the end date falls on. The count is the nights between the two dates, and the page says so, so 1 September to 30 September reads 29 rather than an unexplained 30.

Days betweenLoading today's date.

Mode

Start

End

Adding a month keeps the day number when it can. 31 January plus one month is 28 February (29 in a leap year), and the line under the result says when that happened instead of rolling quietly into March. Weekday counts drop Saturdays and Sundays only. For public holidays use the business days calculator; for hours and minutes between two moments, the duration calculator.

Common questions

Is the end date included in the count?: The day count is the nights between the two dates: Monday to the next Monday is 7, and 1 September to 30 September is 29. If you want both dates counted, add one. The weekday and weekend-day rows do count both dates, because "how many working days in September" means the 1st through the 30th, and the label under each figure says which convention it uses.
How are the months worked out?: Whole calendar months first, by the same rule as adding a month: 31 January to 28 February is one month and no days, because 31 January plus one month is 28 February. Whatever is left after the last whole month is shown as days. Dividing by an average month length of 30.44 days is where most calculators go wrong.
What if the end date is before the start?: The span is counted backwards and the page says so. Swap the two dates if you would rather read it the other way round.
Does daylight saving change the answer?: No. Both dates are calendar dates, not clock times, so a day stays a day across a clock change. For hours and minutes between two moments on a clock, use the duration calculator.

Dates are calendar arithmetic on the civil calendar, so daylight saving never shifts a result. Adding a month lands on the same day number when it exists and the last day of the month when it does not, and the page says which happened. Weekday counts exclude Saturdays and Sundays only; public holidays are not known.