How to count the days between two dates
There are two ways to count days, and they differ by exactly one day:
- The difference (default): how many days pass from one date to the other. Monday to Wednesday is 2 days. This is how Excel and most calendars count.
- Including both days: how many calendar days the period covers when you count both the first and the last day. Monday through Wednesday is 3 days. Use this for a vacation, a rental period or a course "from March 1 through March 5".
The calculator automatically handles months of 28, 29, 30 or 31 days and leap years.
Examples
- January 1 to December 31, 2026: the difference is 364 days. Counting both days gives 365 days: the whole year.
- March 1 through June 30, 2026: 122 days including both days, of which 87 are weekdays and 35 are weekend days.
- October 6 to December 25, 2026: 80 days, or 11 weeks and 3 days.
- January 1, 2000 to October 6, 2026: 9,775 days, or 26 years, 9 months and 5 days.
Weeks, months and years
As well as the number of days, the calculator shows the difference in weeks and days (divide by 7) and in years, months and days. The latter is trickier than it looks because months are not all the same length. The calculator first counts whole years, then whole months and finally the remaining days, just as you would for someone's age. January 31 to March 1 is then 1 month and 1 day (in a common year).
Weekdays and weekend days
The calculator also counts how many of the days fall on Monday to Friday and how many on Saturday or Sunday. Public holidays are not subtracted here. To take official holidays such as Christmas, Thanksgiving or bank holidays into account, use the working days calculator.
What is it for?
- Deadlines: how many days are left for a payment, an appeal or a notice period? Check whether the deadline is in calendar days or business days.
- Rentals and stays: the number of nights in a hotel is the difference between arrival and departure (the last day is not counted).
- Interest and daily costs: to calculate interest over part of a year you need the exact number of days.
- Personal milestones: how many days have you been together, or how many days old are you? The age calculator shows the latter too.
- Countdowns: for the number of days from today until a date, use the days until calculator.
Doing it in Excel or Google Sheets
In a spreadsheet, subtract one date from the other: =B1-A1 gives the number of days. Add 1 if you want to count both days. For weekdays use =NETWORKDAYS(A1,B1), which counts both days by default. Make sure the cells are formatted as real dates and not as text.
Calendar days or business days?
Legal and contractual deadlines are expressed in calendar days, business days, weeks or months, and the difference can be large: 10 business days usually span two full weeks. Many rules also say that a deadline ending on a weekend or public holiday moves to the next business day, but this varies by country, court and contract, so always check the exact wording.
Frequently asked questions
How many days are there between two dates?
Enter them in the calculator. The default result is the difference; choose "Yes, count both days" for the number of calendar days in the period.
Is the end date included?
Not by default: the result is the number of days that pass. Choose "Yes, count both days" to include the last day, as for a vacation from July 1 through July 14 (14 days).
Does the calculator handle leap years?
Yes. February 29 is counted in leap years such as 2024 and 2028.
How many weeks are there between two dates?
Divide the number of days by 7. The calculator shows it as whole weeks plus remaining days.
How many days are in a year?
365, or 366 in a leap year. A year is a leap year if it is divisible by 4, except century years that are not divisible by 400.
Can I count backwards in time?
Yes, you can choose an end date before the start date; you get the same number of days.
Last reviewed: 2026-10-06. Results are estimates for information only.