Counting days between two dates
The number of days between two dates is the difference between their positions on the calendar. This calculator converts both dates to day numbers and subtracts, which accounts automatically for months of 28, 29, 30 and 31 days and for leap years. From January 1 to March 1, 2026 is 59 days; in 2024, a leap year, the same span is 60 days. By default the count excludes the end date, the same way you would count nights in a hotel: from Monday to Friday is four days. Choose “include the end date” if you need both days counted, for example when counting days of a festival or a work assignment.
Years, months and days
Expressing a long gap as years, months and days is more intuitive than a raw day count. The calculator first counts whole months from the start date to the latest same-day-of-month on or before the end date, then counts the remaining days. From March 10, 2025 to October 15, 2026 is 1 year, 7 months and 5 days. This is the same method used by most people and many legal and HR systems when calculating length of service or the duration of a contract.
Business days
Many deadlines are expressed in business days or working days, which exclude Saturdays and Sundays. The calculator counts every weekday from the start date up to the end date. For example, from Monday, October 5 to Monday, October 19, 2026 is 14 calendar days but 10 business days. Public holidays are not removed, because they differ between countries, states and employers. If your period includes holidays such as Thanksgiving or Christmas, subtract them manually. Shipping estimates, legal notice periods, invoice terms and government processing times often use business days, so it is worth checking which definition applies.
Practical uses
A date difference calculator is useful in many everyday situations: working out how long until a lease or warranty ends, calculating the length of a trip, checking how long ago an event happened, measuring time served at a job, counting days of interest on a loan, or tracking a streak or habit. Project managers use it to measure the time between milestones. Teachers use it to count instructional days. If you want a live countdown to a single date, the days until calculator is quicker, and the age calculator is tuned for birthdays. If the end date is earlier than the start date, the calculator shows the absolute difference and lets you know.
Frequently asked questions
How many days are between two dates?
Enter the start and end dates above. The calculator counts calendar days, including leap days, excluding the end date unless you choose to include it.
Does the count include the start and end dates?
By default it includes the start date but not the end date. Choose “include the end date” to add one day.
Are holidays excluded from business days?
No. Only weekends are excluded, because holidays vary by country and employer.
How many weeks are between two dates?
The results show the gap as whole weeks plus remaining days.