How to use
- Pick a mode: Difference, Business days, Add / subtract or Countdown.
- Enter the dates. Use "Include end day" when both ends should count, for example a hotel stay or a rental.
- Read every unit at once in the result card, then print, copy or share the link.
Worked example: From 15 March 2026 to 20 October 2026
The difference is 7 months and 5 days. In total that is 219 days, which is 31 weeks and 2 days, or 5,256 hours.
Switch to Business days and the same span has 151 working days when Saturday and Sunday are weekends and US public holidays (Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day) are excluded.
In Add / subtract, 31 January plus 1 month gives 28 February, because month arithmetic clamps to the last day of the shorter month rather than spilling into March.
Frequently asked questions
Is the end date included?
By default the start day counts and the end day does not, like a plain subtraction: Monday to Friday is 4 days. Turn on "Include end day" to count both, which gives 5.
How are months and years calculated?
The calendar difference counts whole years, then whole months, then leftover days, the way people say "2 years, 3 months and 10 days". Total days is always exact and does not depend on month lengths.
Which holidays are excluded from business days?
Pick a country and the public holidays for the years in your range are fetched from the free Nager.Date service and cached in your browser for 30 days. If you are offline, the built-in US federal holiday list is used. You can also paste extra dates.
Can I change which days count as the weekend?
Yes. Tap the day chips to choose any combination, for example Friday and Saturday for Gulf countries or a single rest day.
What happens with 31 January plus one month?
The result clamps to the last day of February, 28 or 29 depending on the year. Adding another month then lands on 28 or 29 March, not the 31st.
Does the countdown keep running?
Yes. Once the page is open it updates every second in days, hours, minutes and seconds, and the share link lets anyone open the same countdown.
Are time zones involved?
No. All modes work in whole calendar days in your local time, so a date is the same date everywhere.