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Time & payroll / Date Calculator

Date Calculator

Count the days between two dates, or add or subtract days, weeks, months or years to find a due date, deadline or notice period.

Pick a date

Pick a date

Off: Nov 1 to Nov 2 is 1 day. On: it is 2 days, counting both dates, e.g. for a hotel stay counted in days, a rental period or a notice that includes its last day.

Days between the dates
30 days
720hours
4 wk 2 dweeks and days
0 months, 30 daysmonths and days
FromTue, Oct 20, 2026
To · not countedThu, Nov 19, 2026
Weeks4 weeks, 2 days
Calendar months0 months, 30 days
Total days30

The start date is day 0, so the end date is not counted, the same as subtracting dates in Excel. For working days only, use the business days calculator.

See breakdown

How the date calculation works

  1. Days between dates = end date − start date

    From Wednesday, October 14 to Friday, November 13, 2026 is 30 days: 17 days left in October and 13 in November.

  2. Decide whether the end date counts

    Subtracting dates does not count the end date. Switch on “Include the end date” when both days count, and the same range becomes 31 days.

  3. To add days, count from the day after the start date

    30 days after Wednesday, October 14, 2026 is Friday, November 13. Weeks are 7 days each.

  4. Adding months keeps the day of the month

    1 month after October 14 is November 14. If the month is shorter, the date moves to its last day: January 31 + 1 month is February 28, 2027.

Worked example. An invoice dated Wednesday, October 14, 2026 has a 30-day payment term. October 14 to November 13 is 30 days, so the payment is due on Friday, November 13, 2026. Counting both dates, the same range is 31 days.

Date FAQ

How many days are between two dates?

Subtract the start date from the end date. October 14 to November 13, 2026 is 30 days. Add 1 if both the start and end date should count.

Should I include the end date?

It depends on the rule you are following. Date subtraction and most payment terms do not count the start date. For a period where every day counts, such as a 31-day rental from the 1st to the 31st, switch on “Include the end date”.

How do I add days to a date?

Choose “Add or subtract time from a date”, enter the start date and the number of days. Counting starts the day after the start date, so 30 days after October 14 is November 13.

What date is 90 days from today?

Enter today as the start date and add 90 days. 90 days is about three months, but not exactly: it depends on how many 31-day months fall in between.

How are months added when the day doesn't exist?

The date moves to the last day of the shorter month. January 31 + 1 month is February 28 (29 in a leap year). This matches Excel's EDATE function.

How do I count only business days?

This page counts every calendar day. The business days calculator skips Saturdays, Sundays and US federal holidays.

How do I calculate days between dates in Excel?

Subtract the cells: =B1−A1 gives the days between them. Add 1 to count both dates. =DATEDIF(A1,B1,"m") gives whole months, and =EDATE(A1,3) adds 3 months.

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