Son's Share in Islamic Inheritance
The Son as Asabah: No Fixed Fraction
Unlike wives, daughters, parents, and uterine siblings — all of whom receive specific fixed fractions prescribed in the Quran — a son has no fixed fractional share. Instead, a son is classified as Asabah bi nafsihi: a residuary heir by himself. This means a son takes whatever remains of the estate after all fixed shares have been distributed. If there are no fixed-share heirs at all, the son takes the entire estate.
The Quranic basis is Surah An-Nisa 4:11: "For the male is a share equal to that of two females." This verse establishes the 2:1 ratio when sons and daughters coexist — but the son's share is not stated as a fraction; it is defined by reference to the daughters' portion.
Son as the Only Heir
When a son is the sole heir with no fixed-share heirs present, he takes the entire estate as pure Asabah. If there are multiple sons and no daughters or other heirs, they divide the residue equally — there is no primogeniture (eldest son does not receive more) in Islamic inheritance law. Each son receives an identical share.
Son with Daughters: The 2:1 Ratio (Ta'sib bil Ghair)
When a son inherits alongside daughters, a crucial mechanism called Ta'sib bil Ghair (making others residuary heirs through oneself) applies. The presence of a son converts the daughters from fixed-share heirs (who would otherwise receive 1/2 or 2/3) into Asabah heirs alongside him. The entire residue is then distributed in a 2:1 ratio — each son receives twice what each daughter receives.
| Heirs | Distribution | Example (R 600,000 estate) |
|---|---|---|
| 1 son, 1 daughter | Son 2/3, Daughter 1/3 | Son R 400,000, Daughter R 200,000 |
| 1 son, 2 daughters | Son 2/4, each daughter 1/4 | Son R 300,000, each daughter R 150,000 |
| 2 sons, 1 daughter | Each son 2/5, daughter 1/5 | Each son R 240,000, daughter R 120,000 |
| 2 sons, 2 daughters | Each son 2/6, each daughter 1/6 | Each son R 200,000, each daughter R 100,000 |
How a Son Affects Other Heirs' Fixed Shares
The presence of a son (a "child") reduces several fixed shares. This is called Hajb Nuqsan — reduction rather than complete exclusion:
- Husband: reduced from 1/2 to 1/4
- Wife/wives: reduced from 1/4 (shared) to 1/8 (shared)
- Mother: reduced from 1/3 to 1/6
- Father: moves from pure Asabah to 1/6 fixed + residue (if any remains after daughters)
Heirs Blocked by the Son: Hajb Hirman
A son does not merely reduce some shares — he completely excludes certain heirs altogether. This is Hajb Hirman (total exclusion):
- Grandsons (son's son): completely blocked. The son's son only inherits when no living son exists.
- Full brothers: completely blocked by a son.
- Paternal half-brothers: completely blocked.
- Full sisters (as Asabah): blocked from taking residue — though they may still take their fixed 1/2 or 2/3 if the son scenario involves only daughters as co-heirs; but a son converts them to Asabah participants.
- Nephews (brothers' sons): completely blocked.
- Uncles (father's brothers): completely blocked.
Son vs Grandson: Why Grandsons Are Blocked
A common question in estate planning is: if a son died before the deceased, does the son's son (grandson) step into the father's place? Under Islamic inheritance law, the answer depends on whether any other sons survive. A grandson is completely blocked by a living son — there is no "representation" principle (unlike some civil law systems where a predeceased child's share passes to their children). If one son survives, the grandson through a different predeceased son receives nothing from the Faraid distribution.
This is why estate planning — particularly writing a Wasiyyah — is critical for Muslim families where some children have predeceased the parent but left their own children behind.
Worked Example: Estate with Sons, Daughters, Wife, and Parents
Estate: R 1,200,000. Deceased: male. Heirs: 2 wives, 2 sons, 3 daughters, father, mother.
| Heir | Rule | Share | Amount |
|---|---|---|---|
| Wives (2) | With children → 1/8 shared | 1/8 total | R 150,000 (R 75,000 each) |
| Father | Children present → 1/6 fixed | 1/6 | R 200,000 |
| Mother | Children present → 1/6 | 1/6 | R 200,000 |
| Residue | 1 - 1/8 - 1/6 - 1/6 = 13/24 | 13/24 | R 650,000 |
| Father (residue) | Father is Asabah after 1/6 fixed; but sons present so father gets 1/6 only | — | — |
| 2 sons + 3 daughters (Ta'sib) | 2:1 ratio, 7 parts: sons 2+2, daughters 1+1+1 | R 650,000 / 7 | Each son R 185,714; each daughter R 92,857 |