Leap Year Rules
Leap year checker follows Gregorian calendar logic and is useful for date math, scheduling, fiscal cycles, and system time validation.
Gregorian Rules
- A year divisible by 4 and not divisible by 100 is a leap year.
- A century year divisible by 400 is also a leap year.
- All other years are common years.
Typical Examples
- 2000: leap year (divisible by 400)
- 1900: common year (divisible by 100 but not by 400)
- 2024: leap year (divisible by 4 but not by 100)
- 2023: common year (not divisible by 4)
Why Leap Years Exist
- Earth's orbital cycle is about 365.2422 days. If a calendar always used 365 days, timing would drift over years. Leap years keep calendar dates aligned with astronomy.
FAQ
Are the results accurate?
Results are computed in real time with browser date-time logic and the tool's current rules (such as time zone, inclusive end date, and week-start setting). They are suitable for daily planning and development work; for payroll, legal, or contract settlement, verify against your business policy.
Will my data be uploaded?
No. Data processing is performed locally in your browser by default.