Method

Order of operations

1. Funeral expenses are met from the estate.
2. Debts are settled in full, including any unpaid mahr.
3. Bequests are paid, to a limit of one third of what remains after the first two steps — not one third of the gross estate.
4. What remains is divided among the heirs: the fixed shares first, then whatever is left to the residuary heirs, such as sons.

Fixed shares

Drawn from Qur’an 4:11–12 and 4:176, and from the Sunna. The four Sunni schools agree on all of the following, except where a school is named.

Husband

One half with no child and no child of a son surviving; one quarter where a child or a son’s child survives.

Wife, or wives together

One quarter with no child and no child of a son surviving; one eighth where a child or a son’s child survives. Where there is more than one wife they divide that share equally.

Mother

One third, reduced to one sixth where a child or a son’s child survives or where two or more siblings survive. Siblings reduce her share even when they are themselves excluded from inheriting.

Father

One sixth where a son or son’s son survives. Where there is no son or son’s son but a daughter or son’s daughter survives, one sixth and the residue besides. With no child and no child of a son at all, he takes the whole residue.

Daughters

One half for a single daughter, two thirds shared between two or more — but only where no son survives. A son makes his sisters residuary with him, two shares to the male against one to the female.

Son’s daughters

They stand in place of daughters where no child survives. Behind a single daughter they take one sixth, completing the two thirds due to daughters and son’s daughters together. Behind two or more daughters they take nothing unless a son’s son survives to make them residuary.

Maternal (uterine) siblings

One sixth for a single sibling, one third shared between two or more, divided equally without regard to sex. Excluded by a child or a son’s child, by the father, and by the paternal grandfather.

Full sisters

One half for a single sister, two thirds for two or more, where no son, son’s son, father, full brother, daughter or son’s daughter survives. Alongside a daughter or son’s daughter they instead take the residue, standing in a full brother’s place. With the paternal grandfather they share with him (three schools) or are excluded (Hanafi).

Corrections

Awl — the shares exceed the estate

Every share is reduced in proportion. Accepted by all four schools, following the practice of ‘Umar. In al-Minbariyya the wife’s eighth becomes a ninth.

Radd — a surplus remains

Where the fixed shares leave a residue and no residuary heir survives, the surplus returns to the fixed-share heirs in proportion, the spouse taking no part. The Maliki and Shafi’i schools classically direct such a surplus to the bayt al-mal instead; with no such treasury in the United States, contemporary scholars in both schools generally permit the return. This is one of the points requiring confirmation.

Al-Umariyyatan

Where a spouse and both parents are the only heirs and fewer than two siblings survive, the mother takes a third of what remains after the spouse’s share, rather than a third of the estate.

Where the schools differ

Most families never meet any of these. Where one arises, the calculator applies the position held by the majority of the four schools — or, where they split two against two, a stated default — and says so, and you can switch to any single school instead. The majority is worked out from the table below rather than written down separately, so the two cannot drift apart.

Does the grandfather exclude the brothers and sisters?

The grandfather shares with them, taking whichever of his entitlements is greater. This is the position of the Maliki, Shafi'i, and Hanbali schools, and it is what the calculator applies unless you choose otherwise.

The Hanafi school holds instead: The grandfather takes their place entirely and they inherit nothing.

Does the father exclude his own mother?

The paternal grandmother inherits nothing while the father survives. This is the position of the Hanafi, Maliki, and Shafi'i schools, and it is what the calculator applies unless you choose otherwise.

The Hanbali school holds instead: The paternal grandmother takes a sixth alongside the father.

Where the shares leave the full brothers nothing, do they share the uterine third?

The schools split evenly, so there is no majority to take: Maliki and Shafi'i say yes, Hanafi and Hanbali say no. Where no school is chosen, the calculator applies the Hanafi school's answer: the full brothers take nothing.

Do more distant relatives inherit?

The schools split evenly, so there is no majority to take: Hanafi and Hanbali say yes, Maliki and Shafi'i say no. The tie is broken in favour of yes, because the alternative is not available here: directing an estate to the public treasury means, in this country, escheat to a state, which is not what either school was choosing over a surviving Muslim relative. Choosing Maliki or Shafi'i explicitly does not change the answer: with no treasury for the residue to go to instead, the calculator still gives the distant relative what remains after any spouse's share, the same as Hanafi and Hanbali.

Where the missing treasury changes the answer

Nothing is now declined outright. Two results instead depend on there being no properly administered public treasury to receive a surplus — a condition the classical rule always carried, and which a state that would take the estate by escheat does not meet. Each is shown alongside the classical answer it departs from.

A spouse and nobody else

The spouse takes the fixed half or quarter, and classically the remainder would pass to the bayt al-mal — a spouse being the standard example of an heir who takes no part in the return. With no such treasury the remainder returns to the spouse, who takes everything that passes by inheritance. Al-Mawardi holds that where there is no bayt al-mal, necessity calls for both the return and inheritance through distant kindred.

Distant kindred

Classically the Maliki and Shafi’i schools direct such an estate to the treasury rather than to a daughter’s son or a maternal uncle. Al-Dasuqi reports the Maliki qualification that this holds where the treasury is properly administered, and that otherwise shares may be returned and distant relatives admitted.