| Calendar | Type | Notes |
|---|---|---|
| Gregorian | Solar | Common international standard with leap days every 4 years, skip centuries unless divisible by 400. |
| Islamic (Hijri) | Lunar | Twelve lunar months; moves through seasons roughly every 33 years because it lacks leap month. |
| Hebrew | Lunisolar | Adds a leap month seven times every 19 years, keeping festivals near the solar seasons. |
| Chinese | Lunisolar | Astrological months combined with solar terms; uses leap months and the Metonic cycle. |
| Ethiopian | Solar | Twelve 30-day months plus 5 or 6 added days; new year in September. |