Hisab al-Jummal (Arabic Numerology)

Hisab al-Jummal (حساب الجُمَّل, 'counting the sum') is an Arabic numerological system in which each of the 28 letters of the alphabet is assigned a numerical value from 1 to 1000. The word 'abjad' (أبجد) is a mnemonic of the first letters in the traditional alphabetical order: Alif-Ba-Jim-Dal (analogous to 'alphabet' from Alpha-Beta or Russian 'azbuka' from Az-Buki). Abjad is the name of the letter ordering, not the numerological system itself. The system is rooted in the Semitic tradition of recording numbers through the alphabet and was inherited by the Islamic tradition, where it found extensive application in Sufi mysticism (Ilm al-Huruf, 'the science of letters') and in divination (raml).

The abjad letter ordering allows calculation of the numerical value of any word, name, or fragment of the Quran. A famous example: the numerical value of the name 'Muhammad' in a certain reading coincides with the value of phrases interpreted as indirect evidence of prophetic status. Sufi practitioners use Hisab al-Jummal for meditation on the Names of Allah (the 99 Names) and for constructing numerical tables known as wafq.

The twenty-eight letters of the alphabet are linked to the twenty-eight lunar mansions (manzil al-qamar) — the Arabic system of lunar stations, which constitutes an independent astrological tradition. This letter-number-lunar mansion connection creates a multi-layered symbolic system in which the numerical value of a name is embedded within an astrological and cosmological context.

Within the Errarium atlas, Hisab al-Jummal represents the Arabic and Islamic numerological tradition alongside Hebrew gematria (#17), Pythagorean (#5), Chaldean (#29), and Vedic (#30) systems. Its unique distinction is its living rootedness in active religious practice: unlike systems that exist primarily as esoteric practices, Hisab al-Jummal continues to be used in Islamic spirituality and the folk culture of the Islamic world.