Overview
The date difference calculator shows the duration between two days in several formats: days, weeks, months and years. Useful for planning trips, measuring contract periods or counting down to an event.
Formula
Subtract the start date from the end date, then convert the days into weeks, months and years while accounting for month lengths.
How it works
Enter the start date
Pick the first day of the period.
Enter the end date
Pick the last day; it must be after the start date.
Read the duration
See the period in days, weeks, months and years, with an inclusive end-date option.
Worked examples
Example 1: a holiday
From July 1 to July 15: 14 days, or two weeks.
Example 2: a contract
From January 1, 2025 to January 1, 2026: 365 days, or one year.
Frequently asked questions
Does the calculation include both start and end dates?
The main difference excludes the end date. We also show an inclusive value if you need it.
Can I count business days only?
This calculator counts calendar days. A business-day calculator is coming soon.
What if the end date is before the start date?
You will see an error. Swap the dates to get a positive duration.
How are leap years handled?
We count February 29 when it exists, so the duration is exact rather than assuming 365 days per year.
This calculator is for educational and informational purposes only and is not a substitute for professional advice.