Whether you need the Islamic date of your birth, an old document or an upcoming event, converting between the Gregorian and Hijri calendars is a common need. This guide explains how to convert a Gregorian date to Hijri, gives a quick mental formula, and explains why answers sometimes differ by a day. For exact results, use our free Islamic Date Today (Hijri Converter) converter.
Two different calendars
| Feature | Gregorian | Hijri |
|---|---|---|
| Based on | The Sun | The Moon |
| Year length | 365 or 366 days | 354 or 355 days |
| Month length | 28 to 31 days | 29 or 30 days |
| Year 1 begins | Traditional birth of Jesus (AS) | Hijrah, 622 CE |
| New day starts | Midnight | Sunset |
The quick approximate formula
Because a Hijri year is about 97% of a Gregorian year:
Hijri year ≈ (Gregorian year − 622) × 33 ÷ 32
For 2026: (2026 − 622) × 33 ÷ 32 = 1,404 × 1.03125 ≈ 1,447.9. So most of 2026 falls in 1447 AH, with 1448 AH beginning around mid-2026.
To go the other way:
Gregorian year ≈ Hijri year × 32 ÷ 33 + 622
For 1447 AH: 1,447 × 32 ÷ 33 + 622 ≈ 2,025.2, so 1447 AH began in mid-2025.
Why do results differ by a day?
- Moon sighting: in Pakistan, months begin when the crescent is sighted locally. A calculated calendar may differ by one day.
- Calendar system: Saudi Arabia’s Umm al-Qura calendar is calculated astronomically; tabular calendars use fixed rules.
- Sunset: an Islamic day begins at sunset, so an evening event may already fall on the next Hijri date.
Example conversions
Use the converter for exact dates, but as rough examples:
| Gregorian | Hijri (approx.) |
|---|---|
| 14 August 1947 | 27 Ramadan 1366 |
| 1 January 2000 | 24 Ramadan 1420 |
| 1 January 2026 | about 11 Rajab 1447 |
Common uses
- Finding the Islamic date of a birthday
- Calculating zakat due dates, which follow the Hijri year; see the Zakat Calculator
- Planning Ramadan and Eid; see Days Until Ramadan
- Reading old documents dated in AH
Age in Hijri years
Because Hijri years are shorter, your age in Hijri years is slightly higher. A person who is 30 Gregorian years old is about 30.9 Hijri years old. Calculate your exact age with the Age Calculator.
For the history behind the calendar, read the history of the Hijri calendar, and for the months, see Islamic month names and meanings.
Frequently asked questions
How do I convert a Gregorian year to Hijri?
Approximately, (Gregorian year − 622) × 33 ÷ 32.
Why does the Hijri date differ between countries?
Because of local moon sighting and different calendar systems.
When does an Islamic day begin?
At sunset.