Date Difference Calculator
This date difference calculator counts the days between two dates and shows the span in weeks, in years, months and days, and as weekdays (Monday to Friday). You can choose whether to include the end date in the count.
Result
358 days
| In weeks | 51 weeks, 1 day |
|---|---|
| In years, months and days | 11 months, 24 days |
| Weekdays (Mon–Fri) | 256 |
| Hours | 8,592 |
Weekdays exclude Saturdays and Sundays but not public holidays.
How to Count the Days Between Two Dates
The number of days between two dates is the end date minus the start date. By convention, the start date is counted and the end date isn’t: from Monday to Tuesday is 1 day. Ticking “Include the end date” adds one day, which is the right count for things like the number of days of a trip or event.
Weeks
Weeks = days ÷ 7, with the remainder as extra days.
Years, months and days
The calculator steps forward one whole month at a time from the start date, then counts the remaining days. Months have different lengths, so a span of 11 months and 24 days isn’t the same number of days in every year.
Weekdays
Every full week has 5 weekdays. The calculator counts those, then checks the leftover days one by one, skipping Saturdays and Sundays.
Worked Example
From January 1, 2026 to December 25, 2026:
- Days: 358
- Weeks: 358 ÷ 7 = 51 weeks and 1 day
- Years, months and days: January 1 + 11 months = December 1, plus 24 days, so 11 months, 24 days
- Weekdays: 51 full weeks give 255; the extra day, Thursday December 24, makes 256
Tips
Deadlines in business days
For a deadline of “10 business days”, count weekdays and then skip any public holidays your organization observes.
Ages and anniversaries
To find an age in years, months and days, the age calculator is set up for birth dates and next-birthday countdowns.
Hours rather than days
For the time between two clock times on the same day or overnight, use the time duration calculator.
Frequently Asked Questions
How many days are there between two dates?
Subtract the start date from the end date. From January 1 to December 25, 2026 is 358 days. The calculator counts every calendar day and takes leap years into account.
Should I include the end date?
It depends on what you're counting. The days between Monday and Friday is 4, but if you're counting days of an event that runs Monday through Friday, both ends count, which makes 5. Tick "Include the end date" for the second kind of count.
How many weekdays are between two dates?
The calculator counts Monday to Friday in the span. From January 1 to December 25, 2026, there are 256 weekdays. Public holidays aren't removed, because they vary by country, state and employer, so subtract any that apply.
How many days are in a year?
365 in a common year and 366 in a leap year. Leap years are every 4 years, except century years that aren't divisible by 400, so 2028 is a leap year and 2100 won't be.
How many weeks are between two dates?
Divide the number of days by 7. 358 days is 51 weeks and 1 day. The result shows whole weeks plus the days left over.
What if the end date is before the start date?
The calculator measures the span backwards and gives the same number of days, so the order of the dates doesn't change the answer.
Related Calculators
- Age CalculatorExact age in years, months and days, and days to the next birthday.
- Time Duration CalculatorHours and minutes between two times, including overnight.
- Time Card CalculatorWeekly hours, overtime and gross pay from daily start and end times.
- Due Date CalculatorEstimated due date from last period, conception or IVF transfer.
- Percentage CalculatorPercent of a number, what percent X is of Y, and percent change.
Sources & Assumptions
- National Institute of Standards and Technology (NIST) — Time and Frequency from A to Z, "Leap year" (Gregorian rule: century years are leap years only if divisible by 400)
- Days are counted from the start date up to, but not including, the end date unless "Include the end date" is ticked. Weekdays are Monday to Friday; public holidays are not excluded.
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