Islamic Fiqh > Inheritance and wasiya > Dividing shares: qasm and aoul
The share division method: the common base, aoul cases (denominator increase) and standard examples.
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Updated on 06 October 2026 at 10:50 PM
The estate is calculated in equal shares that the jurists call "arrows" (siham): every fixed share is brought back to a fraction of the mass. Example from the books: a mother and 4 paternal uncles: the mother takes the third, the uncles share the 2 thirds as agnates: the base is 3 shares, one for the mother, 2 for the uncles; since the 2 shares do not spread into whole shares for 4 heads, one multiplies: 2 times 3 equals 6. The mother then takes 2 shares of 6, and each uncle one share.
When the fixed shares exceed the base, the denominator of all the heirs is increased proportionally. Example from the books: a husband, the 2 parents and 6 daughters: the base is 12: to the husband 3 shares (the quarter), to the father 2 (the sixth), to the mother 2 (the sixth), to the 6 daughters 8 (the 2 thirds): total 15. The mass rises from 12 to 15: the husband 3 shares, the father 2, the mother 2, the daughters 8 of 15; the daughters' fraction no longer falls exactly on the 2 thirds, but the distribution remains valid; to get whole shares per head, one multiplies the mass by the denominator of the group's share: 3 times 15 equals 45 shares.
The principle "to the male the share of 2 females" governs the residue: the agnates share in equal shares where the male counts double the female (agreement; sura an-Nisa 11).
When the mass no longer fits any group, the jurists confront each class's shares with its number of heads and adjust by multiplication, with or without aoul; the faraid books detail these procedures (Al-Ikhtiyar, al-Jawhara an-Nayyira, the Sharh al-Kabir with its glosses).
Every estate calculation follows 3 steps: set the fixed shares, find the common base, then adjust by aoul or multiplication. The schools' examples provide ready matrices for the most common families.