Khums Calculator
Enter your yearly surplus to calculate the 20% Khums due.
Reviewed by the ToolNestr Editorial Team — July 2026
How the Khums calculator works
Khums, meaning “one-fifth”, is an Islamic financial obligation to give 20% of certain surplus wealth. It is observed as an annual duty especially within the Shia tradition, where it is paid on the profit or income that remains unused at the end of a person’s Khums year, after meeting their legitimate living expenses. This calculator does the arithmetic for you: enter the surplus amount and it returns the Khums due and the portion you keep.
The calculation itself is simple — one-fifth of the surplus — but deciding what counts as surplus requires care. You first cover a year of genuine expenses: food, rent or mortgage, clothing, debts, medical costs and the customary needs of your household. Whatever income is left over and unspent at your Khums date is the base on which the 20% is calculated. The tool keeps everything on your device and stores nothing.
Because rulings on Khums vary between schools and between religious authorities, treat the result as a guide to the maths rather than a final verdict on what you owe. Many people consult the rulings of their marja’ on questions such as how to treat business capital, gifts, or items bought but not yet used. Use the figure here as a starting point and confirm the details with a trusted scholar.
Worked example
If, at the end of your Khums year, 10,000 of income remains after all legitimate expenses, then Khums = 10,000 × 0.20 = 2,000, and you keep 8,000. The 2,000 is then distributed according to the rulings you follow.
Khums and Zakat compared
Khums — 20%
Paid on annual surplus income and certain specific gains, once a year on your Khums date. Central in the Shia tradition.
Zakat — 2.5%
Paid by all Muslims on qualifying wealth held above the nisab for a lunar year. Use the Zakat calculator alongside this tool.
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Frequently asked questions
What is Khums?
Khums means “one-fifth”. It is an Islamic obligation, observed especially in the Shia tradition, to pay 20% of certain surplus income each year. The classic categories include surplus annual profit, mined wealth, treasure-trove and certain other gains.
Who pays Khums?
Khums is a defined obligation primarily in the Shia (Ja’fari) school. Many in the Sunni tradition apply the term mainly to spoils of war (ghanimah) rather than annual income. Follow the rulings of the school and authority (marja’) you adhere to.
What counts as surplus?
Surplus is what remains of your income at the end of your Khums year after deducting legitimate living expenses — food, housing, clothing, debts and customary needs. Khums is then due on what is left over and unused.
How is Khums different from Zakat?
Zakat is 2.5% on qualifying wealth held for a lunar year above the nisab, due from all Muslims. Khums is 20% on annual surplus and specific gains. Many who pay Khums also pay Zakat where it applies.
Sources & references
This tool uses standard formulas and reference values from:
- • The Qur’an — e.g. Surah an-Nisa (4:11–12, 4:176) for the fixed inheritance shares (fara’id).
- • Sahih al-Bukhari & Sahih Muslim — hadith on inheritance, zakat and nisab thresholds.
- • AAOIFI and recognized fiqh councils (e.g. Islamic Fiqh Academy) for contemporary rulings. aaoifi.com
Rulings differ between scholars and schools (madhahib), and calculated astronomical times/dates may differ from local sighting. Confirm with a qualified scholar before acting.