How Zakati calculates
Every number in the app comes from the same four steps. Each one is explained below in plain words, then in detail, and worked through with one example household so you can check the arithmetic yourself.
Example prices: gold $4,000 and silver $48 a troy ounce. The app uses each day's market prices.
01
What Zakati counts
Zakat on savings is due on wealth you could spend or sell: cash, gold and silver. Zakati tracks those three. You add an account for each place you keep them, a bank account, a jewellery box, a bag of coins, and record what is in it.
You type everything in yourself. Zakati never connects to your bank.
Cash
Bank accounts and cash at home, each in its own currency.
- USD
- EUR
- GBP
- SAR
- AED
- PKR
- + 124 more
Gold
Jewellery, coins and bars, by weight and purity.
- 24k
- 22k
- 21k
- 18k
- 14k
- 10k
Silver
Coins, bars and silverware, by weight.
- grams
- kilograms
- troy ounces
In detail
- Cash accounts hold an amount in one currency.
- Gold accounts hold a weight and a purity: 24, 22, 21, 18, 14 or 10 karat.
- Silver accounts hold a weight, valued at the price of pure silver. There is no purity setting for silver.
- Metal can be entered in grams, kilograms or troy ounces. It is stored in grams, and each entry remembers the unit you used.
- Cash can be held in any of 130 currencies, each account in one.
- A balance can never go below zero. Zakati checks this every time you add or back-date an entry.
02
Turning it all into one number
To compare your wealth with the nisab, everything has to be in one currency. Zakati values every account in US dollars, using the market prices for that day, then adds them up.
Gold is valued by how much pure gold it contains. A 21 karat ring is 21 parts gold in 24, so 120 grams of it holds 105 grams of gold.
The example household, on one day
$42,675
- SavingsCash in USD$28,400
- Wedding set120 g of 21k gold$13,503
- Coins500 g of silver$772
In detail
Metal prices are quoted per troy ounce, which is 31.1035 grams. The example household works out like this:
- Savings28,400 USD × 1
- $28,400
- Pure gold120 g × 21 ÷ 24
- 105 g
- Gold value105 g × $4,000 ÷ 31.1035
- $13,503
- Silver value500 g × $48 ÷ 31.1035
- $772
- Totalsavings + gold + silver
- $42,675
Cash in other currencies is multiplied by that day's exchange rate to the dollar. The app shows totals in your chosen currency, but the rules are applied to the dollar figures.
03
The nisab, priced every day
The nisab is the least you must own before zakat applies. Zakati uses the gold nisab: 85 grams of pure gold, priced on the day.
Because the gold price moves, so does the nisab. It is recalculated for every day of your year, and each day's wealth is compared with that same day's nisab.
The nisab on the same day
$10,931
85 g × $128.60 a gram
- 85 g of goldZakati uses this$10,931
- 595 g of silver$918
In detail
- Gold, per gram$4,000 ÷ 31.1035
- $128.60
- Nisab85 g × $128.60
- $10,931
Some scholars use a silver nisab of 595 grams instead. At the example silver price of $48 an ounce ($1.54 a gram) that is only $918. Zakati does not offer the silver standard: if you follow it, your threshold is lower than the one the app shows, and you may owe zakat when the app says you do not.
04
A year measured by the moon
Zakat falls due once your wealth has stayed above the nisab for a full hawl: one year of the Hijri calendar. A Hijri year follows the moon, so it is 354 or 355 days, about 11 days shorter than the solar year.
When you set up Zakati you give the date your zakat was last due or paid; from then on Zakati follows your hawl from your daily balances. A hawl closes the day before the same Hijri date comes round. The example hawl runs from 2 Ramadan 1447 to 1 Ramadan 1448, 355 days.
One hawl, month by month
- Ram30
- Shaw29
- Dhu Q30
- Dhu H29
- Muh29
- Saf30
- Rab I29
- Rab II30
- Jum I30
- Jum II29
- Raj30
- Sha30
30 days29 days
10 days shorter, so your due date moves about 11 days earlier each solar year.
In detail
- Zakati uses the Umm al-Qura calendar, the official calendar of Saudi Arabia and the one built into iPhone and Android. Month lengths come from a fixed table taken from the same source your phone uses, so the app and your phone always agree on the date.
- The closing day is found by counting one Hijri year, never a fixed number of days: it is the day before the same Hijri date next year. If that date doesn't exist (a 30th in a 29-day month), the next hawl starts on the month's last day and this one closes the day before.
- Dates are stored in the Gregorian calendar and converted to Hijri when shown, so a record never shifts between calendars. Hijri years 1418 to 1500 are supported.
- The hawl is always counted in Hijri years, even if you choose to see dates in the Gregorian calendar.
05
Checked on every day of the year
It is not enough to be above the nisab at the start and the end. Zakati values your holdings on every day of the hawl, with that day's prices, and compares the total with that day's nisab.
If every day stays at or above the nisab, the hawl is complete. If any day falls below, the hawl is broken and nothing is due for it. The next day your wealth is back at or above the nisab, a new hawl starts on its own.
355 daily checks
Days at or above
337
Days below
18
Below the nisab from 22 Rabi’ al-thani to 9 Jumada al-awwal 1448
A new hawl starts on 10 Jumada al-awwal 1448, the first day back above the nisab.
In detail
- Each day is a checkpoint with two numbers: your total in dollars and the nisab in dollars. The hawl holds only when the total is at least the nisab on every checkpoint.
- Days below the nisab are grouped into continuous runs, each with a first and last date, which is what the app shows you.
- Zakati also records the lowest your wealth reached and the highest the nisab reached during the year, and the dates of each.
- Deposits, withdrawals and balance updates count from the day you date them. The closing day still belongs to the hawl that is ending; the next one starts the day after.
- Exactly equal to the nisab counts as above it.
06
What is due, and when
When the hawl is complete, zakat is 2.5% of your total wealth on the closing day, valued with that day's prices. That is one fortieth.
Zakat is worked out on the whole total, not account by account, and only for a hawl that held.
On 1 Ramadan 1448
$42,674.93
× 2.5%
$1,066.87
- Hawl begins2 Ramadan 1447
- Hawl closes1 Ramadan 1448
- Next hawl begins2 Ramadan 1448
In detail
- Wealth on 1 Ramadan 1448cash + gold + silver
- $42,674.93
- Zakat$42,674.93 × 2.5%
- $1,066.87
- When you pay, record it as a withdrawal from the account you paid from, on the day you paid.
- Money is handled as whole millionths of a dollar. Zakat is the total divided by 40, rounded half up to the nearest millionth.
- It is then converted to your currency at the due date's exchange rate and shown to the cent.
- The next hawl starts the day after the closing day. Each completed hawl is kept in your History with its closing holdings and graph, and can't be changed afterwards.
07
Prices, rates and precision
Gold and silver prices and currency exchange rates come from a market data provider and are updated daily. Each day of your hawl is valued with that day's prices, not today's.
Markets close at weekends and on holidays, so those days use the last trading day's prices.
The numbers are stored in a way that keeps them exact, even for currencies worth a tiny fraction of a dollar.
A very weak currency, 1 unit in US dollars
$0.000000571…
- Stored exchange raterate × 10¹²
- 571,429
- Stored metal price$4,000 an ounce × 10⁶
- 4,000,000,000
When a currency drops zeros
Syria replaced 100 old pounds with 1 new pound on 1 January 2026. Amounts you enter for earlier dates are converted to the new pound before they are valued.
- 1,000,000 old SYP on 15 December 2025
- 10,000 SYP
In detail
- Each price is the day's closing price, collected every evening at 22:00 UTC, after the New York markets close.
- A day is valued with the latest price on or before it, never one from later.
- Gold and silver are priced in dollars per troy ounce; one troy ounce is 31.1034768 grams.
- Exchange rates are stored as whole numbers scaled by 10¹², which keeps about six significant figures even for currencies worth less than a millionth of a dollar. Metal prices are stored in millionths of a dollar.
- When a currency drops zeros but keeps its code, as the Syrian pound did, amounts dated before the change are converted to the new unit first.
08
What Zakati leaves to you
Zakati does the arithmetic of widely followed rules. It is not a religious ruling, and some questions depend on your situation and the school you follow.
For these, ask a scholar you trust. Zakati gives you the exact figures to take to them.
Questions about your own zakat?
We can't give rulings, but we're happy to explain any number the app shows you, or how it got there.
In detail
- Debts you owe or are owed are not deducted or added.
- Business stock, shares, property and crops are not tracked.
- Jewellery you wear is counted. Some schools exempt it; leave it out if yours does.
- A dip breaks the hawl. Some scholars look only at the start and end of the year; if you follow that view, Zakati will show nothing due where you may owe zakat.
- The silver nisab is not available.
- Local moon sighting is not applied. Where months begin by sighting, dates can differ from Umm al-Qura by a day.