About this date difference calculator
Find out exactly how much time separates two dates, in calendar years, months, and days, as well as the total number of days and weeks. This is useful for measuring a project timeline, a contract term, time served, or the gap until a deadline or anniversary, without counting on a calendar by hand. Unlike the age calculator, which always measures from a birth date to today, this tool accepts any two dates you choose, in either order of entry as long as the start is not after the end.
How the date difference calculator works
The calendar breakdown counts whole years and months using anniversary dates, then reports the remaining days, mirroring how the age calculator counts a birthday. Total days and total weeks are a straight count of days between the two calendar dates.
Date Difference Calculator examples
2026-01-01 to 2026-09-19
0 years, 8 months, 18 days · 261 total days · 37 total weeks
2024-01-01 to 2025-06-15
1 year, 5 months, 14 days · 531 total days · 75 total weeks
Limitations & privacy
The start date must be on or before the end date. Maximum span is bounded by JavaScript's native date range, and dates before 1900 are not specifically validated for calendar accuracy.
Inputs and results stay in this browser. Only tool identifiers are stored for your recently used tools. You can clear that history from the directory.
Date Difference Calculator: frequently asked questions
How is this different from the age calculator?
The age calculator always measures from a birth date to today or another chosen date. This tool measures between any two dates you enter, for tasks unrelated to age.
Does it count the start and end day both?
Total days is the count of days between the two calendar dates, so the start date itself is day zero, matching how most deadline and duration calculations work.
Can I get just the answer in weeks?
Yes, the total weeks figure is the total days divided by seven and rounded down to a whole week.
Updated September 20, 2026