Reference
The rules الفرائض
How an estate is divided under Islamic law — the principles the calculator applies.
Order of distribution
Before any heir inherits, four claims are met from the estate in order:
- 1. Funeral expenses — a dignified burial.
- 2. Debts — everything owed to people and to God.
- 3. Bequest (waṣiyya) — up to one third of what remains, to non-heirs.
- 4. The fixed shares (farāʾiḍ) — the rest is divided among the heirs by the rules below.
The calculator's “Debts, funeral & bequest” section nets the estate down to the amount that is actually divided, capping the bequest at one third.
The fixed shares — al-furūḍ
Allah names the shares of close relatives in the Qurʾan (chiefly 4:11, 4:12 and 4:176). Each fraction is conditional on who else survives.
- · Husband — when there is no child
- · A sole daughter
- · A sole son's daughter
- · A sole full sister
- · A sole paternal sister
- · Husband — with a child
- · Wife (or wives, shared) — with no child
- · Wife (or wives, shared) — with a child
- · Two or more daughters
- · Two or more son's daughters
- · Two or more full sisters
- · Two or more paternal sisters
- · Mother — no child and fewer than two siblings
- · Two or more maternal siblings (shared equally)
- · Father — with a child
- · Mother — with a child or two or more siblings
- · Grandfather — with a child
- · Grandmother
- · A sole maternal sibling
- · Son's daughter completing a daughter's ⅔
- · Paternal sister completing a full sister's ⅔
Residuary heirs — al-ʿaṣaba
After the fixed shares are paid, whatever remains goes to the residuary heirs (ʿaṣaba) — the agnatic relatives, nearest first: the son, then the son's son, the father, the grandfather, then the brothers and their lines. Where a male and female of the same rank inherit together (a son and a daughter, a brother and a sister), the male takes the share of two females (2:1).
A daughter or a sister normally takes a fixed share, but becomes a residuary when she inherits alongside her brother, or — for a full or paternal sister — alongside a daughter.
Blocking — al-ḥajb
A nearer heir can exclude a more distant one, either completely (ḥajb ḥirmān) or by reducing their share (ḥajb nuqṣān). For example: a son blocks the son's son and all the siblings; the father blocks the brothers; the mother is reduced from ⅓ to ⅙ when a child or two or more siblings survive.
The calculator shows blocked heirs greyed out with the reason they were excluded, so nothing is hidden.
ʿAwl & radd
ʿAwl (over-subscription): sometimes the fixed shares add up to more than the whole estate — for example a husband (½) with two full sisters (⅔). The base of the problem is raised so the shares fit, and everyone is reduced in proportion.
Radd (return of surplus): the opposite — the fixed shares fall short and there is no residuary heir to take the remainder. The surplus is returned to the fixed-share heirs in proportion, with one exception: the spouse never shares in the radd.
The four schools — al-madhāhib
For the overwhelming majority of families, the four Sunni schools — Ḥanafī, Mālikī, Shāfiʿī and Ḥanbalī — give exactly the same result. They diverge mainly in one situation: when a grandfather inherits alongside full or paternal siblings (al-Jadd wa al-Ikhwa).
The Ḥanafī school treats the grandfather as a father, so he excludes the siblings entirely. The Mālikī, Shāfiʿī and Ḥanbalī schools let him share with them (muqāsama), taking whichever is best for him: a share alongside them as a brother, one third of the remainder, or one sixth of the whole estate. The Mālikī and Shāfiʿī schools also apply al-Mushtaraka, letting full brothers share the maternal siblings' third. The calculator computes all four and tells you when they differ.