How the date difference calculator works
The calculator converts both dates to calendar days and subtracts them, so leap years and different month lengths are handled automatically. By default it counts the days between the dates, which means the start date is counted and the end date is not — the same way you would count nights in a hotel. Choose "include end date" if you need both days counted, such as for a rental that covers both the first and last day.
What you get
You will see the total number of days, the same span in weeks and days, the difference expressed in years, months and days, and the number of weekdays (Monday to Friday) in the range. Weekday counts are useful for estimating business days, but they do not remove public holidays, so subtract any federal or company holidays that fall in your range.
Example
From January 1, 2024 to January 1, 2025 there are 366 days, because 2024 was a leap year; the same span in 2025 has 365. From Monday, October 19, 2026 to the following Monday there are 7 days and 5 weekdays.
Handy uses
Use it to count down to a vacation, wedding or due date, to check a 30-, 60- or 90-day deadline, to work out how long you have held an investment (more than one year for long-term capital gains treatment), or to calculate notice periods and contract terms. If you enter the dates in reverse order, the calculator swaps them and tells you, so you always get a positive result.
Frequently asked questions
Does the result include the start date?
By default the result counts from the start date up to, but not including, the end date. Choose the option to include the end date to add one day.
Are holidays excluded from business days?
No. The weekday count excludes only Saturdays and Sundays.
Does daylight saving time affect the count?
No. The calculator uses whole calendar dates, so clock changes do not affect the result.
How many weeks are in a year?
A common year has 52 weeks and 1 day; a leap year has 52 weeks and 2 days.
Results are estimates for educational purposes only and are not financial, tax, legal or medical advice. See our disclaimer. Last reviewed 2026-10-22.