Days Between Dates Calculator
Choose two calendar dates and decide whether to exclude the start date or include both endpoints. The result also separates the elapsed span into full weeks and extra days.
General calendar calculation only. Contract, visa, benefit, court, travel, and filing deadlines can use special inclusion, cutoff-time, holiday, or jurisdiction rules.
Enter your scenario
Use the details that match your situation. Your estimate stays in this browser.
How this estimate works
- Each YYYY-MM-DD input is validated as a Gregorian calendar date, including the century leap-year rule.
- Elapsed mode subtracts the start-date ordinal from the end-date ordinal; inclusive mode adds one to count both endpoints.
- No local clock time is created, so daylight-saving transitions and timezone offsets cannot add or remove a day.
Official reference
- U.S. Naval Observatory: introduction to calendars and Gregorian leap-year rule
- NIST: timekeeping FAQ and day-interval reference
This page uses the internationally accepted Gregorian civil calendar described by the U.S. Naval Observatory. Check the rules that govern any legal or administrative deadline separately.
Frequently asked questions
Does the calculator include the start date?
Elapsed mode excludes the start date. Inclusive mode adds one day so both the start and end dates are counted.
Can daylight saving change the answer?
No. The calculation uses Gregorian calendar-day ordinals rather than local timestamps, so timezone and daylight-saving offsets do not affect it.