Why is gold not always 100% pure?

Pure 24K gold is very soft — it bends and scratches easily with normal wear. Mixing gold with harder metals (copper, silver, zinc, palladium) creates an alloy suitable for jewellery that holds its shape and resists damage. Higher-karat pieces (24K, 22K) feel slightly softer; lower-karat (14K, 10K) is much harder and more scratch-resistant.

Does lower karat mean lower quality?

Not necessarily — it means less gold per weight. 10K gold is more durable than 24K and costs less per gram, making it popular for everyday Western jewellery like rings. 22K is the South Asian preference for store-of-value jewellery with a richer color. Choose the karat that fits how the piece will be worn, not just the purity.

Why does 22K gold look more yellow than 18K?

Because it has more actual gold. Gold is naturally a warm yellow color. As karat decreases, alloy metals (especially copper and silver) shift the color — 14K often looks paler, 10K more like brass, white gold or rose gold varies based on which alloys are added. Pure 24K has the deepest yellow.

How does this relate to Zakat?

Islamic Zakat on gold is calculated on pure gold weight, not gross jewellery weight. So for 10 tola of 22K gold, Zakat applies to the 9.17 tola of actual pure gold, not the 10 tola total. This calculator's pure-gold output is exactly what you would enter into a Zakat calculator for accurate compliance.

Can you recover pure gold from jewellery?

Yes, through a process called refining (usually via fire assay or acid dissolution), but it requires specialized equipment and labs. Professional refineries charge a fee (typically 3–8% of recovered metal value) and return ~95% of the theoretical pure content. For small jewellery pieces, melt-and-recast by a jeweller is usually more economical than formal refining.

Is a higher-karat piece always worth more?

Not proportionally. A 100 g 22K piece has about 22% more pure gold than a 100 g 18K piece — the value scales linearly with karat. But higher-karat jewellery is softer and may have higher making charges offset, so the final retail price doesn't scale quite linearly. Always compare metal value (this calculator) plus making charges separately.

What alloy metals are in 18K gold?

Depends on the color. Yellow 18K mixes gold with silver and copper. White 18K uses nickel, palladium, or silver (and rhodium plating). Rose 18K uses more copper. Green 18K is gold + silver. All these are 18/24 = 75% gold by weight — only the 25% alloy composition varies, producing different colors.

Gold Purity & Impurity Calculator

Gold & Silver

Find the pure gold and impurity content of any gold item based on weight and karat.

Gold & Silver

Gold Purity & Impurity Calculator

Generated on April 24, 2026

Gold Weight

Karat (Quality)

?What is the Gold Purity & Impurity Calculator?

A gold purity calculator splits any weight of gold into its two components: the pure 24K gold content and the alloy (impurity) content. This is essential for insurance declarations, inheritance valuations, Zakat computation (which is based on pure gold weight), melting and recasting calculations, and anyone comparing 22K vs 18K purchases. The calculator accepts any weight unit (grams, tola, masha, ratti, or ounces) and any karat from 10K through 24K, showing both the pure gold equivalent and the impurity (alloy) breakdown in all common units, along with a visual purity-vs-impurity split bar.

The Formula

Pure Gold = Total Weight × (Karat ÷ 24). Impurity = Total − Pure.

Karat expresses gold purity as parts out of 24. So 22-karat gold is 22 parts pure gold and 2 parts alloy (usually copper, silver, or zinc for hardness and color), making 22/24 = 91.67% purity. 18K is 75% pure. Multiplying the total weight by this fraction gives the pure-gold content; the remainder is the impurity or alloy weight. Notice that jewellers often use the terms 'purity' and 'alloy' interchangeably — they describe the same split from opposite sides of the ratio.

Practical Examples

10 tola of 22K gold contains 10 × 22/24 = 9.17 tola of pure gold and 0.83 tola of alloy.

50 g of 18K gold contains 50 × 18/24 = 37.5 g of pure gold and 12.5 g of alloy metals.

A 100 g 14K US necklace contains only 58.33 g of actual gold — the rest is copper, silver, or zinc alloy.

For Zakat purposes: 50 tola of 22K gold has 45.83 tola of pure gold, which is compared against the Nisab threshold for obligation.

A 200 g 21K Middle-Eastern bangle set contains 175 g pure gold (21/24 × 200) and 25 g alloy.

Melting down a 15 g 14K ring yields only 8.75 g of recoverable pure gold — useful to know when considering melting for remake.

Frequently Asked Questions

They express the same thing two ways. Karat is out of 24 (22K, 18K, etc.). Purity is out of 100 or as a fraction (91.67%, 75%). Karat value ÷ 24 × 100 gives the purity percentage. This calculator shows both so you can verify whichever is on your jewellery stamp or receipt.

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Gold & Silver Weight Converter

Convert between tola, masha, ratti, grams, and troy ounces for precious metals.

Gold Purity & Impurity Calculator

Gold Purity & Impurity Calculator

?What is the Gold Purity & Impurity Calculator?

The Formula

Practical Examples

Frequently Asked Questions

What is the difference between purity and karat?

Why is gold not always 100% pure?

Does lower karat mean lower quality?

Why does 22K gold look more yellow than 18K?

How does this relate to Zakat?

Can you recover pure gold from jewellery?

Is a higher-karat piece always worth more?

What alloy metals are in 18K gold?

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