Date Difference
Count days, weeks or years between two dates.
Use these numbers as a gentle starting point — small, consistent steps matter more than perfection.
How to use Date Difference
Count the days, weeks, months or years between any two dates with a free date calculator.
Open Date Difference on toolpermarket and enter your values in the fields below.
In the Start date field, enter the earlier of the two dates. Use the real calendar date, year included.
In the End date field, enter the later date to count toward. Swap them and the result goes negative.
Press Calculate to compute the result. The output appears immediately below the form. You can change any input and run it again to compare results.
Read the result and use it as needed. If the number looks off, re-check your inputs and run it again — the math is deterministic, so the same entries always return the same answer.
Worked example. From 2026-01-01 to 2026-07-21 is 201 days, or about 6 months and 20 days.
Tips for accurate results.
It counts whole days, inclusive of the boundaries you set.
Use it for project spans, not just birthdays.
Leap years are handled automatically, so trust the count.
When to use Date Difference. Measuring a project or trip duration. Counting days until an event or deadline. Confirming an age or tenure in days.
When you actually reach for this
- You need the number of days between two dates for a contract, lease or project.
- You want to count weekdays only, excluding weekends.
Where this tool stops being accurate
- The plain day count includes weekends and holidays; use the weekday option if your deadline skips Saturdays and Sundays.
- It does not adjust for your local calendar holidays.
Frequently asked questions
Does it include both the start and end day?
The tool reports the number of whole days between the two dates. Whether you count the endpoints depends on context — a hotel stay from Monday to Thursday is 3 nights but 4 calendar days. The day count is exact; you decide if you need to add or drop a boundary. You’ve got this.
How are leap years handled?
Automatically. February 29 adds its day in leap years, and the difference is correct across year boundaries without you doing anything. The Gregorian calendar rules are built in. You’ve got this.
Why is my month count not a round number?
Months have unequal lengths, so a span expressed in months and days is approximate by nature. The day total is exact; the months-and-days form is a convenience that cannot be perfectly uniform because not every month is the same size. You’ve got this.
Does it count both the start and end date?
It counts whole days between the two dates, so the end date itself is not added. If you need inclusive counting, add one day. You’ve got this.