Gold Purity Chart: Karat to Percentage Conversion Table

Divide the karat by 24, multiply by 100, and the mystery goes out of gold purity. A 22-carat bangle works out to 91.67% gold. An 18-carat ring is 75%. That one sum is all a gold purity chart really encodes, and this page lays it out in full: every grade from 6K to 24K converted to its percentage purity and its millesimal fineness number, alongside the BIS hallmark stamp used in India and where each grade typically shows up. The chart matters beyond curiosity. The fineness number stamped on a piece decides its resale price, and it decides how much a lender may offer against it in a gold loan. So the guide also explains how to read a BIS hallmark, and how purity feeds into the per-gram value when jewellery is pledged. Bookmark the table; the rest of the page explains it.

What Karat Means, and How to Convert It to a Percentage

Karat measures gold purity in parts per 24. Pure gold is 24 karat. Anything below that is gold mixed with other metals, usually copper, silver or zinc, added for strength.

The conversion is one line of arithmetic. Purity % = (karat ÷ 24) × 100. So 22K works out to (22 ÷ 24) × 100 = 91.67%. And 18K is (18 ÷ 24) × 100 = 75%.

Millesimal fineness says the same thing per 1,000 parts instead of per 100. A 22-carat piece is 916 fine, meaning 916 parts of gold in every 1,000. An 18-carat piece is 750 fine. Jewellers in India stamp the fineness number, not the karat, which is why the hallmark on a 22K chain reads 916. Two systems, one fact. That is the whole karat to percentage gold conversion.

Complete Gold Purity Chart: All Karat Grades at a Glance

The table below covers every commonly referenced grade. The BIS hallmark stamp column shows the fineness number as it appears on jewellery hallmarked in India; grades outside the BIS list are not hallmarked domestically.

Note: Purity percentages and fineness values follow standard conversion arithmetic; BIS hallmarking grades are as notified under Bureau of Indian Standards rules and may be updated from time to time.

Two rows do most of the work in India. 22K (916) dominates jewellery because it balances high purity with enough hardness for daily wear. 24K stays in coins, bars and investment products, since pure gold is too soft to hold a setting.

How to Read a BIS Hallmark Stamp on Gold Jewellery

Turn any hallmarked piece over and the stamp tells its story in a few small marks. Under the current HUID system, a BIS hallmark carries exactly three components:

• The BIS logo, a triangular mark, confirming certification by the Bureau of Indian Standards.
• The purity and fineness grade, such as 916, 750 or 585. This is the number to check first, since it confirms the karat.
• The HUID, a six-digit alphanumeric Hallmark Unique Identification number assigned to each individual article.

Older pieces hallmarked before 2021 may show additional marks, including the assaying centre's and the jeweller's identification, which the HUID system has since folded into a central database. The HUID can be looked up on the BIS Care app, which shows the registered details of the article, including the jeweller and the hallmarking centre. Hallmarking is mandatory in India for gold jewellery above a specified weight threshold under Bureau of Indian Standards rules, and the HUID system has been in force since 2021. In practice, a buyer needs to check just two things: the triangle, and the fineness number. If the stamp says 916, the piece is 22 carat. Simple as that.

Why Gold Purity Matters for a Gold Loan

Lenders work from the metal, not the making. The loan amount comes from the net gold weight multiplied by the applicable per-gram rate for the assessed purity. Higher purity, higher per-gram value, higher eligible loan.

A quick comparison shows the gap. Ten grams of 22K gold carries 9.167 grams of pure gold. Ten grams of 18K carries only 7.5 grams. At the same gold rate, the 22K pieces support a noticeably larger loan even though both sets weigh the same on the scale.

Under the RBI (Lending Against Gold and Silver Collateral) Directions, 2025, effective 1 April 2026, valuation follows a fixed method: lenders take whichever is lower, the 30-day average price or the closing price of the preceding day, as published by IBJA or a SEBI-recognised exchange, with the reference rate applied according to the assessed purity of the gold. Stones and attachments are deducted, since only the net metal is valued. The assessment happens in the borrower's presence and a certificate itemises purity, weight and value. IIFL Finance typically accepts gold jewellery in the 18 to 22 carat range for a gold loan, so even a 750-stamped ring can be pledged; it is simply valued at its actual gold content. The loan itself is then capped by the RBI's tiered loan-to-value limits: 85% on loans within ₹2.5 lakh, dropping to 80% in the ₹2.5 to ₹5 lakh band and 75% past that. Borrowers can check their eligibility at any IIFL Finance branch.

Is Higher Karat Always Better? The Durability Trade-Off

A common assumption runs: more karat, better gold. For investment, yes. For jewellery, not quite. Pure and near-pure gold bends, scratches and loses shape with daily wear, which is why nobody sets a diamond in 24K. The alloying metals in 18K and 14K give a piece the stiffness to hold stones and survive decades of use. So the right grade depends on the job: 24K for coins and bars, 22K for classic ornaments, 18K for studded work. The gold purity chart above is a value reference, not a quality ranking.

Conclusion

Gold purity is one formula and one stamp. The formula converts karat to a percentage; the stamp, the BIS fineness number, confirms what the piece actually contains. Between the carat percent table gold reference above and the three-mark hallmark explained here, a buyer can decode any piece in the jewellery box in under a minute. That knowledge pays twice: once at the counter, where the fineness number anchors the price, and again at the lender's desk, where assessed purity sets the loan value. For anyone considering pledging jewellery, a gold loan from IIFL Finance values the metal transparently, in the borrower's presence, against the published IBJA benchmark. All values discussed here are indicative and the final loan amount depends on assessed purity, prevailing rates and applicable guidelines.

Disclaimer : The information in this blog is for general purposes only and may change without notice. It does not constitute legal, tax, or financial advice. Readers should seek professional guidance and make decisions at their own discretion. IIFL Finance is not liable for any reliance on this content. Read more