Date Difference
Measure the days and weeks between two calendar dates.
How to use this tool
Select the start and end dates. The result gives elapsed days and weeks. Tick the inclusive option if you want to count both calendar dates. An end date before the start date is rejected.
A worked example
From 1 January to 8 January there are 7 elapsed days, or exactly 1 week. Counting both dates produces 8 days.
How it works & what to check
This is a calendar-day calculation, not a business-day calculation. Weekends and public holidays are included. Approximate months use 30.436875 days per month; they are not full calendar months.
Common questions
Does the calculator include the end date?
The default measures the distance between dates. Choose “Count both start and end dates” when you need an inclusive count.
Does daylight saving change the answer?
No. The date-only values are compared using UTC calendar dates.
Can I use this for a deadline?
It can help with arithmetic. Confirm whether your deadline includes weekends, holidays, the starting date or a specific time of day.