The science of inheritance
Islamic inheritance (faraid) is a precise system laid out in the Quran. The main shares are given in Surah an-Nisa 4:11-12, after which Allah says: 'These are the limits set by Allah' (an-Nisa 4:13). Distributing an estate by these shares is an obligation and an act of justice.
How it works
After the deceased's debts are paid and any valid bequest (up to one-third, not to an heir) is carried out, the remainder is divided. Some heirs receive fixed shares (fard) such as a half, a quarter, or a sixth; the residue passes to the residuary heirs (asaba). Some heirs block others. If the fixed shares exceed the estate they are reduced proportionally (awl); if a surplus remains with no residuary it returns to the fixed-share heirs (radd).
A guide, not a fatwa
This calculator handles the common cases - spouse, children, parents, grandmothers, and full or maternal siblings - using rules agreed across the Sunni schools. It does not handle every situation (for example a grandfather inheriting alongside siblings, paternal half-siblings, or grandchildren), and the schools differ on some cases. Always have the final distribution confirmed by a qualified scholar or an Islamic inheritance authority before acting on it.
Why the shares are fixed
Inheritance is one of the few areas where the Quran legislates in numbers: specific fractions for parents, spouses, and children, laid out in Surah an-Nisa and sealed with the reminder that these are limits set by Allah. The wisdom shows in what the system prevents. Because shares are fixed by law and not by the deceased, wealth cannot be steered by favoritism or withheld from daughters, wives, or elderly parents; every rightful heir arrives at the estate already owning a defined portion of it. Scholars called this knowledge half of all knowledge and urged its study precisely because it protects the weakest heirs at the exact moment emotions and interests run highest - the days after a death.
Using this calculator
Select who survived the deceased - spouse, sons, daughters, parents, and siblings for the common cases - and the calculator applies the fixed Quranic fractions, working in exact arithmetic rather than rounded decimals so shares like a sixth and an eighth combine without drift. Each heir is shown with their fraction, the percentage it represents, and, if you enter the estate value, the amount per person. Use it to understand a family situation, check an executor's math, or teach the science with live examples. For real estates - especially with debts, bequests, or less common heir combinations - take the result to a scholar, as the final ruling belongs there.