To calculate if a year is a leap year, follow these steps based on the Gregorian calendar:
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Divide the year by 4. If it's divisible without any remainder, it might be a leap year (continue to step 2). If it's not divisible, it's not a leap year.
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If divisible by 4, check if it's also divisible by 100. If it's divisible by 100, it might not be a leap year (continue to step 3). If it's not divisible by 100, it is a leap year.
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If divisible by both 4 and 100, check if it's also divisible by 400. If it's divisible by 400, it is a leap year. If it's not divisible by 400, it's not a leap year.
Here's a summary in a table:
| Divisible by 4? | Divisible by 100? | Divisible by 400? | Leap Year? |
|---|---|---|---|
| Yes | No | N/A | Yes |
| Yes | Yes | Yes | Yes |
| Yes | Yes | No | No |
| No | N/A | N/A | No |
Examples:
- 2024: Divisible by 4 (2024/4 = 506). Not divisible by 100. Therefore, 2024 is a leap year.
- 1900: Divisible by 4 (1900/4 = 475). Divisible by 100 (1900/100 = 19). Not divisible by 400 (1900/400 = 4.75). Therefore, 1900 is not a leap year.
- 2000: Divisible by 4 (2000/4 = 500). Divisible by 100 (2000/100 = 20). Divisible by 400 (2000/400 = 5). Therefore, 2000 is a leap year.
- 2023: Not divisible by 4 (2023/4 = 505.75). Therefore, 2023 is not a leap year.
In essence, a year is a leap year if it is divisible by 4, unless it is a century year (divisible by 100) that is not divisible by 400.
