Free Online Date Difference Calculator
Calculate days, weeks, and months between dates
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About this tool
Calculate the exact number of days, weeks, months, and years between any two dates with this free date difference calculator. Enter a start and end date to see the total difference broken down by years, months, and days, plus total days, weeks, and business days (weekdays only). Great for figuring out how many days until a deadline, how long between two events, or counting business days for project planning. The calculator handles month-end edge cases correctly and includes a swap button to quickly reverse the dates. All calculations happen in your browser.
How to use Date Difference Calculator
- Enter start date. Pick or type your start date.
- Enter end date. Pick or type your end date.
- View results. See the difference in years, months, days, weeks, and business days.
Frequently Asked Questions
Months are calculated using calendar months. January 15 to March 15 is exactly 2 months. For end-of-month edge cases, the calculator rounds down — January 31 to February 28 counts as 1 month, not 0.
Business days are Monday through Friday, excluding Saturday and Sunday. This calculator does not exclude public holidays since they vary by country and region.
The difference is calculated from the start date to the end date. If both dates are the same day, the difference is 0 days.
A typical year has about 260 business days (52 weeks × 5 weekdays). After subtracting common US holidays, most workers have roughly 250 working days per year.
Yes. Enter any two dates in any order — the calculator shows the absolute difference. Use the swap button to reverse the start and end dates.
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