An Islamic inheritance calculator takes a short list of facts about who survives you, applies the fixed shares in the Quran and the rules of residue, and returns a percentage for each heir. In Australia the only provider that publishes a free tool with its methodology stated is MuslimWills, whose calculator says it follows the majority of scholars (the Jumhur). Wasiyyah and LawBridge publish no calculator. The catch is that a calculator divides a notional estate, while an Australian estate leaks: superannuation is paid by a fund trustee rather than the will, a jointly owned home passes to the survivor, and a family provision claim can override the shares. This guide shows how the tool works, runs four households through it, and says when a lawyer is not optional.
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What a faraid calculator asks and what it does with the answers
The MuslimWills calculator starts with your gender and whether you are Islamically married, then asks for a count of sons and daughters, paternal grandsons and granddaughters (a son's children only; a daughter's children are not eligible), whether your father, mother, paternal grandfather, paternal grandmother and maternal grandmother are alive, and then counts of full, paternal and maternal brothers and sisters, full and paternal nephews, paternal uncles and paternal cousins. Each input carries an eligibility note: adopted, step and illegitimate children are excluded, a secret or undocumented marriage does not count, and only the father's line of grandparents and uncles is eligible. Those notes are the classical rules of the science of shares (ilm al-faraid) compressed into form fields.
Behind the form the calculator does three things in order. It assigns fixed Quranic shares (fard) to the heirs who have one: a spouse, parents, daughters without sons, and certain siblings. It gives the residue to the agnatic heirs (asaba), typically sons with daughters at two shares to one, or the father, or brothers. Then it handles the two cases where the fractions do not add up: if the fixed shares exceed the estate the shares are scaled down proportionally (awl), and if they fall short and there is no residuary heir the surplus is returned to the blood heirs (radd). Methodology matters most in that last step, which is why MuslimWills' statement that it follows the Jumhur, and its note that other schools of thought are being added, is worth more than it looks. The faraid rules explained article walks through the fractions themselves.
Four Australian households run through the shares
The examples below use a net distributable estate of $800,000, meaning what is left after funeral costs, debts, any unpaid zakat and any bequest have come off. LawBridge's Islamic wills page sets out that order: funeral expenses and debts including zakat first, then up to one-third as bequest (wasiyyah), then the fixed shares. The fractions are the majority-school results a Jumhur-based calculator will return; check them against the tool yourself, because the point of this section is to show you how to read the output.
| Household | Fixed shares | Residue | On $800,000 |
|---|---|---|---|
| Husband dies: wife, two sons | Wife 1/8 | Sons share 7/8 equally | Wife $100,000; each son $350,000 |
| Wife dies: husband, one daughter, mother | Husband 1/4, mother 1/6, daughter 1/2 | 1/12 unallocated, returned (radd) to daughter and mother in proportion | Husband $200,000; daughter and mother split $600,000 at 3:1 |
| Husband dies: wife, father, mother, no children | Wife 1/4; mother 1/3 of what remains, which is 1/4 | Father takes the rest, 1/2 | Wife $200,000; mother $200,000; father $400,000 |
| Husband dies: second wife, two sons from first marriage, one daughter from second, one stepdaughter | Wife 1/8 | Sons and daughter share 7/8 at 2:2:1; stepdaughter nothing by shares | Wife $100,000; each son $280,000; daughter $140,000; stepdaughter $0 |
The second row is the one to study. A husband, a daughter and a mother all hold fixed shares and nobody is a residuary heir, so the fractions leave one-twelfth unallocated. Jumhur-based tools return it to the daughter and the mother in proportion to their shares and exclude the husband, which is why the daughter ends with more than half; a tool following a different school could return it differently or not at all. If your family shape leaves a gap like this, note what the calculator did with it and ask the will drafter to confirm the school you intend to follow. The fourth row shows the other limit: the stepdaughter is excluded from the shares by every school, and the only way to provide for her is a bequest of up to one-third, which the calculator does not model.
The one-third bequest and why the calculator runs after it
LawBridge's page states the rule that governs everything a Muslim can choose: up to one-third of the net estate can be left to non-heirs, including non-Muslims and charities, and the remaining two-thirds or more must follow the fixed shares. A calculator divides whatever you feed it, so if you intend a bequest, deduct it first and run the tool on the remainder. On the $800,000 estate above, a one-third bequest of $266,667 to a stepdaughter, a waqf or a charity would leave $533,333 to be shared, and every figure in the table would fall by a third. MuslimWills builds the bequest into its will builder, with a slider for the wasiyyah percentage and an option to establish a waqf through Awqaf Australia, which designed and funds the platform. The waqf and charitable bequests guide covers what a bequest to a waqf can do.
What the calculator cannot see in an Australian estate
A faraid tool assumes everything you own passes through your will. In Australia three large categories do not, and this is where a share schedule drawn from a calculator can be wrong by hundreds of thousands of dollars without anyone noticing until after the funeral. The estate planning hub sets out the full structure; the three leaks are below.
- Superannuation: LawBridge's own insight page states that super does not automatically form part of a deceased estate and that the fund trustee decides who receives the death benefit, considering any nominations. A calculator cannot see a balance that a trustee will pay to a nominated spouse in full, so a binding nomination to the estate or shares that mirror faraid is the fix; the super death benefits and the Islamic estate article explains the choices.
- Jointly owned property: a home held as joint tenants passes to the surviving owner by survivorship and never enters the estate. If the family home is the main asset, the calculator is dividing something that is not there. Holding as tenants in common puts each person's share into their own estate.
- Family provision claims: LawBridge's FAQ confirms that an Islamic will can be contested in court, either on validity or by an eligible person claiming inadequate provision under Australian law. A calculator produces shares; it cannot predict whether a spouse or child will treat those shares as inadequate. The family provision risk article covers who can claim.
- Trusts, companies and life insurance: assets held in a family trust or a company are owned by the structure, and a life policy with a nominated beneficiary is paid outside the estate. Each needs its own instruction.
- Debts and zakat: the calculator divides a net figure, so unpaid zakat, a halal home finance balance and funeral costs must be estimated and deducted before you run it.
MuslimWills, Wasiyyah and LawBridge: who publishes what
The three names Australians meet when they search for an Islamic will sit at different tiers, and only one of them gives you a calculator. The comparison below uses what each site publishes on 9 September 2026; our Islamic will services comparison reviews the will products in depth.
| Provider | Inheritance calculator | Stated methodology | Will product and price | Who reviews the will |
|---|---|---|---|---|
| MuslimWills | Free, public, no login | Jumhur (majority); other schools being added | Online will builder, $149 plus GST; two witnesses to sign | Compliance team; template designed by Australian lawyers and Islamic scholars |
| Wasiyyah | None published | Not stated on the site; wills verified by scholars and lawyers | Online will, $89; operating since 2012; first six months of updates included | Internal review for Shariah and Australian law, with phone support |
| LawBridge | None published | Mawarith (faraid) rules; one-third bequest cap stated | Custom drafting by a law firm, quote-only; offices in Martin Place, Chullora and Melbourne | Solicitors; liability limited under Professional Standards Legislation |
The practical reading is this. MuslimWills is the only place to produce a share schedule for free before you commit to anything, and its stated school lets you check whether the output matches your own. Wasiyyah is the cheapest will at $89 and has the longest track record among the online platforms, but you arrive without a calculation and rely on its questionnaire to produce the shares. LawBridge is where you go when the calculator output is the beginning of the problem rather than the end of it: blended families, assets in trusts or companies, a probable family provision claim, or an estate with property overseas, which its October 2026 insights discuss.
How to use a calculator properly before you see a will drafter
- List everything you own and how it is held: sole name, joint tenants, tenants in common, super, trust, company, life policy. Separate what passes by will from what does not.
- Estimate debts, funeral costs and unpaid zakat, and subtract them to reach a net estate figure for the will assets only.
- Decide whether you want a bequest of up to one-third and to whom, deduct it, and run the calculator on the remainder.
- Enter your family exactly as the tool asks, reading the eligibility notes; a step-child or an adopted child is not an heir by shares and needs the bequest.
- Save the percentage output and compare it with a second method, such as the worked rules in our faraid explainer, especially if awl or radd applied.
- Take the schedule, the asset list and the super nomination to the will provider, and ask how each non-will asset will be steered toward the same shares.
The decision: when a calculator is enough and when it is not
If your assets are in your sole name or held as tenants in common, your family fits a standard shape (spouse, children, perhaps parents), you have no step-children or dependants outside the heirs, and your super nomination already points where you want it, a free calculator plus an online will from MuslimWills or Wasiyyah will produce a schedule a court can follow, and the Islamic will hub lists what else the will must contain. If you own the family home as joint tenants with a spouse, hold assets through a trust or company, have a blended family or a child you intend to provide for outside the shares, or expect a relative to feel short-changed, the calculator is a starting document and the drafting belongs with a lawyer such as LawBridge, because the shares it produces will be undone by survivorship, trustee discretion or a family provision claim unless the structure is fixed first. In both cases, run the tool now rather than later: the schedule it gives you is the clearest way to see whether your super nomination, your property title and your will are pulling in the same direction. Facts checked against muslimwills.com.au, wasiyyah.com.au, lawbridge.com.au on 9 September 2026.
Frequently asked questions
Is there a free Islamic inheritance calculator for Australia?
Yes. MuslimWills publishes a free calculator on its site with no login required. It states that it follows the majority (Jumhur) opinion and that other schools of thought are being added. Wasiyyah and LawBridge do not publish a calculator on their sites, so MuslimWills' tool is the only Australian one with a stated methodology.
Which school of thought does the MuslimWills calculator follow?
The calculator page says it follows the opinions of the Jumhur, the majority of scholars, and that the provider is working to include other schools of thought. The school matters most when the fixed shares do not add up to the whole estate and a return (radd) or reduction (awl) rule has to be applied, so check the output against your own school in those cases.
Does an Islamic will calculator include superannuation?
No. A calculator divides the estate you enter, and super does not automatically form part of an Australian estate; LawBridge's insight page notes that the fund trustee decides who receives the death benefit, considering any nominations. To bring super into line with faraid you need a binding nomination to the estate or to heirs in the right proportions, which the calculator cannot set up.
How does the one-third bequest work with a calculator?
Deduct the bequest before you run the tool. LawBridge's page states that up to one-third of the net estate may go to non-heirs such as charities or non-Muslims, and the rest follows the fixed shares. On an $800,000 net estate a full one-third bequest is $266,667, leaving $533,333 to be divided by the calculator among the heirs.
Can a step-child or adopted child inherit under an Islamic will in Australia?
Not through the fixed shares. The MuslimWills calculator states that adopted, step and illegitimate children are not eligible heirs. A step-child or adopted child can be provided for through the bequest of up to one-third, or through assets that pass outside the will such as a super nomination or a life policy, which is a reason to involve a drafter rather than rely on the tool.
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Can a family provision claim override the calculator's shares?
Yes. LawBridge's FAQ confirms that an Islamic will can be contested in court, including by an eligible person claiming they did not receive adequate provision under Australian law. The calculator cannot predict that. Reducing the risk means documenting reasons, considering the needs of each eligible person and, in complex families, having a lawyer draft the will.
