ToolPilot
Date calculator
Find the difference between two dates or add/subtract days from a date.
Days between two dates
Difference
0 days
- Total days
- 0
- Weeks
- 0.0
- Full weeks
- 0
How it works
The "days between" mode computes the calendar difference in years, months, and days, accounting for varying month lengths. Total days uses the absolute millisecond difference divided by 86,400,000. The add/subtract mode shifts a date by a given number of days, handling month and year rollovers automatically.
FAQ
Does this account for leap years?
Yes. The calculator uses JavaScript's built-in Date object which correctly handles leap years and varying month lengths.
What timezone does this use?
All calculations use your local timezone. Dates are treated as midnight in your local time, so there are no timezone offset issues.
Can I subtract days?
Yes. In the "Add / subtract days" mode, enter a negative number to go back in time.
How is "weeks" calculated?
Weeks is total days divided by 7. "Full weeks" is that value floored — useful when you need to know how many complete 7-day periods fit.