Date Difference Calculator
Find the exact number of days, weeks, months, or years between any two dates.
Select a start and end date to calculate the exact difference. The result is displayed in years, months, weeks, and days, plus totals in days, weeks, and months. Working days (Mon–Fri) and weekend days are also counted separately — useful for project planning and deadline calculations.
Date calculations are valuable across many fields. Project managers use them to track sprints and milestones. Legal professionals calculate statutes of limitations and contract periods. HR departments compute employment tenure for benefits eligibility. The working-days count is especially practical — knowing how many business days fall within a window helps allocate resources and set realistic delivery targets.
Frequently Asked Questions
How many days are between two dates?
The calculator subtracts the start date from the end date and returns the exact number of days. For example, from January 1, 2024 to July 1, 2024 = 182 days (since 2024 is a leap year).
How are working days calculated?
Working days are Monday through Friday. The calculator counts each day in the range and classifies it as a working day or weekend. Note: public holidays are not excluded, as they vary by country.
How many days are in a month?
Months have 28, 29, 30, or 31 days depending on the month and whether it's a leap year. The average month is approximately 30.44 days. For precise calculations, the calculator uses exact calendar dates rather than averages.
How many weeks are between two dates?
Divide the number of days by 7. The calculator shows both the total in full weeks and the breakdown (e.g., 2 years, 3 months, 1 week, 4 days).
Can I calculate the number of business days for a project?
Yes. The "Working days" figure excludes Saturdays and Sundays. For project planning, subtract any known public holidays from this number to get the net working days available.
How many days are in each month?
January, March, May, July, August, October, and December have 31 days. April, June, September, and November have 30 days. February has 28 days (29 in a leap year). A useful mnemonic: count on your knuckles — knuckles are 31-day months, gaps are 30 or 28.
Can I find a future date by adding days to a start date?
This calculator finds the difference between two known dates. To find an end date by adding days, enter your start date and adjust the end date until you reach the desired number of days shown.
How do I calculate employment tenure?
Enter your employment start date as the start and today (or your end date) as the end. The result in years, months, and days gives your exact tenure. For example: started March 1, 2020, today June 8, 2026 = 6 years, 3 months, 7 days.
What is ISO 8601 date format?
ISO 8601 is the international standard for writing dates as YYYY-MM-DD (e.g., 2025-12-31). It eliminates ambiguity in formats like 05/06/2025, which can mean May 6 (US format) or June 5 (European format).
How many working days are in a typical year?
A standard year has 365 days with 52 weekends (104 days), leaving 261 working days (Mon–Fri). Subtracting public holidays (typically 8–13 days depending on country) gives approximately 248–253 net working days per year.