How it works
The dates are treated as calendar dates at midnight UTC, so daylight-saving changes do not alter the day count. January 1 to January 2 is 1 day. Equal dates give 0 days.
Days = end date − start date; weeks = days / 7
Worked example
Show example inputs and result
Start date: January 1, 2026 · End date: October 8, 2026.
- Days between dates
- 280
- Weeks
- 40
Questions and answers
Does this count working days?
No. It counts every calendar day, including weekends and holidays. If the end date precedes the start date, the difference is negative.
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method reviewed: October 8, 2026 · Methods & accuracy