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Comparing calendars
Islamic vs Gregorian
The Islamic calendar is purely lunar and adds no leap month, so its year runs about eleven days shorter than the Gregorian one and cycles through every season in roughly thirty-three years.
| Attribute | Islamic | Gregorian |
|---|---|---|
| Type | Lunar | Solar |
| Origin | Islamic tradition | A 1582 reform of the Julian calendar, under Pope Gregory XIII |
| Year | 12 lunar months (about 354 days) | 365 days, or 366 in a leap year (365.2425 on average) |
| Months | 12, of 29 or 30 days | 12, of 28–31 days |
| Week | 7 days | 7 days |
| Leap rule | None — so it falls about 11 days earlier against the seasons each year | One leap day every 4 years — but not in a century year unless it divides by 400 |
| Counts years from | The Hijra, 622 CE (AH) | The traditional birth of Christ (AD / CE) |
| Where it’s used | Islamic religious life worldwide; civil use in several countries | The world’s common civil calendar |
See this moment on each: Islamic (Hijri) calendar · Gregorian calendar. Or convert a specific date into both.