Hijri to Gregorian Date Conversion: The Umm Al-Qura Calendar Explained

Saudi Arabia officially uses the Umm Al-Qura calendar, a lunar Islamic calendar based on astronomical calculations rather than moon sightings. Converting between Hijri and Gregorian dates is a daily need for millions of people — but why is it so tricky?

Why Hijri and Gregorian Don't Match

The Gregorian calendar follows the solar year (365.25 days). The Islamic Hijri calendar follows the lunar year, which is roughly 354 days. That 11-day annual difference means Hijri dates drift backward relative to Gregorian dates each year.

The 12 Hijri Months

1. Muharram (30 days)
2. Safar (29 days)
3. Rabi al-Awwal (30 days)
4. Rabi al-Thani (29 days)
5. Jumada al-Awwal (30 days)
6. Jumada al-Thani (29 days)
7. Rajab (30 days)
8. Shaban (29 days)
9. Ramadan (30 days)
10. Shawwal (29 days)
11. Dhu al-Qidah (30 days)
12. Dhu al-Hijjah (29 or 30 in leap year)

A regular Hijri year is 354 days; a leap year is 355 days.

How the Umm Al-Qura Calendar Differs

Traditional Islamic calendars depend on physical moon sighting. Umm Al-Qura uses precomputed astronomical data, giving Saudi Arabia a fixed and predictable calendar for administrative use (schools, salaries, visas).

Manual Conversion Formula

The simplified formula:

Hijri Year ≈ (Gregorian Year − 622) × 33/32

This gives an approximation; for exact conversion, use tables or a calculator.

Common Use Cases

• Checking your birthday in Hijri
• Employment contracts in Saudi Arabia
• Visa expiry dates
• Iqama and residency renewal
• Zakat calculation year
• Bank installments

Free Online Converter

Skip the math — our Hijri-Gregorian Converter handles both directions and includes an Hijri age calculator.

Age in Hijri Years

Because a Hijri year is ~11 days shorter, your Hijri age is slightly higher than your Gregorian age. Someone 30 in Gregorian is about 30 years, 11 months in Hijri. Over a lifetime, the difference reaches 2-3 years.

FAQ

Which dates are official in Saudi Arabia?

Both are used, but government and religious matters follow Hijri. Business and international transactions often use Gregorian.

When does Ramadan start?

The 1st of the month Ramadan (9th Hijri month). Umm Al-Qura publishes the exact Gregorian date well in advance.

Manage Your Business in Both Calendars

Daqiq supports both Hijri and Gregorian in reports, invoices, and payroll — perfect for Saudi businesses.