Gold Purity Calculator
Convert gold karat to purity percentage and BIS hallmark number. Calculate the pure-gold content and melt value of any piece of jewellery.
Pure Gold (24K equivalent)
18.320g
Out of 20g 22K piece
Purity (BIS)
916
91.60%
Alloy Weight
1.680g
Copper / silver / zinc
Pure Gold Value
₹1,75,872
Melt Value
₹1,75,872
BIS Hallmark stamp for 22K = 916
Verify the 6-digit HUID on your jewellery at the BIS Care app. See BIS Hallmark & HUID explained.
Karat to purity reference table
| Karat | BIS Hallmark | Purity % | Common Use |
|---|---|---|---|
| 24K | 999 / 9999 | 99.9% - 99.99% | Investment coins, bars, Gold ETF/SGB underlying |
| 22K | 916 | 91.6% | Standard Indian jewellery |
| 18K | 750 | 75.0% | Diamond/gemstone settings, western jewellery |
| 14K | 585 | 58.5% | Studded, machine-made western |
| 9K | 375 | 37.5% | Cheap costume gold — not BIS-hallmarked in India |
For full karat comparison, see 18K vs 22K vs 24K gold comparison. To verify hallmark and HUID, read BIS Hallmark & HUID explained.
Disclaimer: Calculator assumes accurate karat stamp. Always verify BIS Hallmark and 6-digit HUID against the BIS Care app database before paying for jewellery.
Frequently Asked Questions
What is the difference between 22K and 916 gold?+
Both mean the same thing — 22K gold contains 91.6% pure gold, so the BIS hallmark stamps it as '916'. The remaining 8.4% is alloy metals (copper, silver, zinc) added for strength.
Is 24K gold 100% pure?+
24K is 99.9% or 99.99% pure — BIS marks it as 999 or 9999. True 100% pure gold doesn't exist commercially because all refining processes leave trace impurities.
Why is jewellery rarely made of 24K gold?+
24K is too soft for jewellery. It deforms easily, scratches within weeks of daily wear, and cannot hold stone settings securely. Indian jewellery is mostly 22K; western diamond jewellery is mostly 18K.
What does '585' mean on gold jewellery?+
585 is the BIS hallmark for 14K gold (58.5% pure). 14K is uncommon in Indian jewellery but common in western and machine-made designs.