How Islamic inheritance works: a plain guide

Most legal traditions leave inheritance largely to a will. Islamic law takes a different path: for certain close relatives, the Qur’an fixes the portion each receives, and distributes the remainder by a clear order of priority. The result is a system that is unusually precise — and, once its logic is clear, unusually fair in its own terms.

This precision is also why a small mistake can quietly distort an entire distribution. Understanding the structure — even at a high level — helps you see what a calculator is doing, and when a question has moved beyond what any tool can settle.

The order of settlement

Before a single share is calculated, the estate passes through a fixed sequence. Each step is completed before the next begins:

1. Funeral expenses — the costs of washing, shrouding and burial are met first.
2. Debts — what the deceased owed is settled from the estate, before heirs receive anything.
3. Bequests (waṣiyyah) — a valid bequest to non-heirs, up to a maximum of one-third of what remains.
4. The fixed shares — only the remainder, the distributable estate, is divided among the heirs.

This ordering matters. A common error is to divide the whole estate among heirs and treat debts as an afterthought; in the Islamic framework, debts and the burial come first, as a matter of justice to creditors and to the deceased.

Fixed shares and residuary heirs

The distributable estate is divided between two kinds of heir. The first are the ashab al-furud — those whose share is a fixed fraction named in the Qur’an. The second are the ʿasaba, the residuary heirs, who take whatever is left once the fixed shares are paid.

The fixed share a person receives is not always the same — it depends on which other heirs are present, and especially on whether the deceased left descendants. A husband, for instance, receives one-half of his wife’s estate if there are no children, but one-quarter if there are. A few of the most common shares:

Sons are the primary residuaries. When sons and daughters inherit together, the remainder after the fixed shares is divided so that each son receives the portion of two daughters — the principle named in the verse above.

Why the shares differ

The most discussed rule — that a son often receives twice a daughter’s share — is frequently quoted without the context that gives it meaning. In the Islamic framework, financial responsibility falls on the man: he provides the dowry (mahr), and he is obliged to maintain his wife, children and dependants. A woman’s wealth, by contrast, is hers alone, with no obligation to spend it on the household.

The shares reflect a division of financial duty, not a measure of worth.

It is also worth noting that this two-to-one ratio is not universal across every case. In a number of situations a woman inherits the same as, or more than, a comparable male relative — the rule applies in specific configurations, not as a blanket principle. The detail here is real, and it is one of several reasons a careful tool, or a scholar, is worth consulting.

Where it gets complex

For a simple family — a spouse, children and parents — the four Sunni schools agree, and the arithmetic is tractable. Beyond that, several mechanisms come into play:

• ʿAwl — when the fixed shares add up to more than the whole estate, every share is reduced proportionally to fit.
• Radd — when the fixed shares leave a surplus and there is no residuary heir, the surplus is returned to the fixed-share heirs (in most schools, not to a spouse).
• Exclusion (ḥajb) — the presence of one heir can reduce or entirely block another; a son, for example, excludes the deceased’s brothers.
• School differences — grandparents alongside siblings, certain grandchildren, and the treatment of the radd are handled differently across the madhabs.

This is the point at which a back-of-the-envelope division becomes unreliable, and where the value of either a well-built calculator or a qualified scholar becomes clear.

Working it out

The Maa’rij inheritance calculator handles the common cases — spouse, children and parents — with the fixed shares, the residue, and the ʿawl and radd adjustments computed for you, each heir shown with the verse their share rests on. It runs entirely in your browser; nothing you enter is stored or sent.