Date Difference Calculator
Get the full duration between two dates in years, months and days.
The Date Difference Calculator expresses the span between two dates the way people talk about age and tenure: '3 years, 4 months and 17 days'. It computes a full calendar breakdown — years, months and remaining days — alongside the totals in days, weeks and hours, so you get both the human-friendly phrasing and the raw numbers.
The breakdown follows how most systems phrase durations: complete years first, then complete calendar months left over, then the remaining days. The tool counts real calendar months (so January 15 to February 15 is exactly one month), and it works correctly across leap years. If you enter the dates in reverse order it still reports a clear positive duration.
Use it for employment and lease tenure, loan terms, subscription lengths, 'time since' milestones like an anniversary or sobriety date, or comparing two durations fairly. All math runs locally in your browser with no sign-up.
Full duration
6 years, 5 months, 22 days
Mar 15, 2020 → Sep 6, 2026
Total days
2,366
Total weeks
338
+ 0 days
Total hours
56,784
The year/month/day breakdown counts calendar months between the dates (e.g. Jan 15 → Feb 15 is exactly 1 month).
How to use the Date Difference Calculator
- Enter the earlier date.
- Enter the later date.
- Read the full breakdown: years, months and days.
- Check the totals in days, weeks and hours below.
- Date order does not matter — the duration is always reported as a positive span.
Frequently asked questions
How do you calculate years, months and days between dates?
The algorithm subtracts dates component by component: years first, then months, then days, borrowing a full month (28–31 days depending on the calendar) when the day numbers do not line up. January 31 to March 1 therefore counts as 1 month and 1 day, not 1 month and −2 days.
What is the difference between calendar months and 30-day months?
Calendar months are the real February–December lengths (28–31 days). Some financial contracts use 30/360 conventions where every month counts as 30 days — this calculator does not; it uses true calendar durations, which is what people mean in everyday speech.
How do I count tenure like 'years of service'?
Count from the start date to today (or the end date) and read the years figure from the breakdown. For exact anniversary-style tenure most HR systems count complete years: starting March 10, 2020 means 5 full years of service on March 10, 2025.
Why are the total days different from years × 365?
Because real years have 365 or 366 days depending on leap years, and months vary in length. The total-days figure is the true calendar count; multiplying the year figure by 365 would be an approximation and is never shown.
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