Date Calculator
Free online date calculator. Find how many days or weeks lie between two dates, or work out what date it is after adding or subtracting days, weeks or months — handy for planning deadlines, projects, trips and countdowns. Results appear instantly and run locally. ProductivityRuns locally
Use this tool
① Difference between two dates
② Add / subtract
How to use
- Difference: pick a start and end date to see the gap.
- Add/subtract: pick a start date, enter an amount and a unit (days/weeks/months).
- The weekday of the result is shown to help with scheduling.
Frequently asked questions
Are both start and end days counted?
The result is the whole-day difference between the two midnights — e.g. the 1st to the 2nd is 1 day. To count both days inclusively, add 1.
How is adding a month at month-end handled?
It advances by calendar month, so January 31 + 1 month lands on the last day of February, matching calendar behaviour.
Can it count business days?
This version counts calendar days; a weekend-excluding business-day mode can be added later.