The name هِجْرة (hijrah) describes the migration of the Islamic prophet Muhammad and his followers from Mecca to Medina in June 622 CE. This also marks the beginning of the Islamic or (lunar) Hijri-calendar, so called التَّقْوِيم الهِجْرِيّ الْقَمَرِيّ
The Muslim calendar is a lunar calendar and doesn’t follow a solar system like the Gregorian or Persian calendar.
Normally, in Arabic, it is marked by the letter ھ. It is written in the form that it has at the beginning of the word (ھ) – and not the stand-alone form: ه.
I am not sure why; maybe so it is not confused with the number 5. The Gregorian or Christian calendar is marked by the Arabic letter مmeaning: مِيلادِيّ, A.D.
So let us come back to our question:
Which (Gregorian) year is, for example, 1435 Hijri? First of all, one lunar year has about 354 days. We need to convert it. The easiest way is to use a corrective factor (354 divided by 365) ≈ 0.97.
This brings us to a formula
1. If you want to convert a Hijri date to a Gregorian date, you need to multiply the original Hijri year by 0.97 and add 622:
Year Gregorian ≈ Year Hijri × 0.97 + 622
2. If you want to convert a Gregorian date to a Muslim date, you have to subtract 622 from the year and multiply it by 1.03:
Year Hijri ≈ (Year Gregorian– 622) × 1.03
In our example, the result is: 1435 x 0.97 + 622 = 2013.95
It is the year: 2014
picture credit: Image by Andreas Lischka from Pixabay