Date Difference
Days, weeks, months between dates
The Date Difference Calculator measures the elapsed time between two dates in multiple units: total days, weeks, months, and years. Useful for project planning, leave requests, contract durations, and any context where you need a clean count between two calendar dates.
What it returns
- Total days between the two dates.
- Total weeks (and remaining days).
- Years, months, and days breakdown.
- Whether the second date is in the past or future.
How it works
Total days is straightforward: convert both dates to a day count (e.g. day-of-year times a year offset) and subtract. The years/months/days breakdown uses the same "borrow" technique as the Age Calculator, anchored to whichever date comes first.
Worked example
From January 15, 2025 to July 28, 2026:
- 1 year, 6 months, 13 days
- ≈ 559 days
- ≈ 79 weeks and 6 days
When this is useful
Project planning, lease durations, paid time off, contract expiration tracking, "how long since..." questions, and any general calendar arithmetic.
Inclusive vs exclusive
By default, the calculator returns the difference between the two dates without including either endpoint twice. If you need to count "from Monday to Friday inclusive" (so Mon, Tue, Wed, Thu, Fri = 5 days), add 1 to the day count. For business days specifically, use the Working Days Calculator instead.
Frequently asked questions
Does this count both endpoints?
No — the difference is the number of days elapsed. From Jan 1 to Jan 2 is 1 day, not 2.
Does it account for leap years?
Yes. The day count is correct across leap years and across century-year edge cases.
What about business days only?
Use the Working Days Calculator, which excludes weekends.