Zakat & Islamic Finance
Gold Karat Calculator
Convert gold weight between karats. The pure gold stays the same — only the alloy around it changes.
Gold Karat Calculator
About the Gold Karat Calculator
Convert a weight of gold from one karat to another. The pure gold stays the same — only the amount of alloy around it changes — so 100 g of 24K becomes about 109 g of 22K carrying the identical gold content.
Enter a weight, the karat it is now, and the karat you want it expressed in. The tool returns the equivalent weight, the pure gold content in grams, and the millesimal fineness that would be stamped on the piece. Add a price per gram and it values the holding too.
This is a metallurgy and conversion tool rather than a religious one. For zakat on gold, where the pure content is what the threshold is tested against, use the gold zakat calculator.
How to use the Gold Karat Calculator
- Enter the weight of your gold and pick the unit.
- Choose the karat you are converting from — what the piece is now.
- Choose the karat you are converting to.
- Optionally add a price per gram to value the piece.
- Select Convert. The table shows the same pure gold expressed in every common karat.
The conversion
Purity = karat ÷ 24
Pure gold = weight × purity
Equivalent = pure gold ÷ target purity
Worked example
100 g of 24K gold, expressed as 22K.
Pure gold: 100 × (24 ÷ 24) = 100 g
As 22K: 100 ÷ (22 ÷ 24) = 100 ÷ 0.9167 = 109.09 g
100 g of 24K equals 109.09 g of 22K
You have not gained gold. You have added 9.09 g of alloy around the same 100 g of gold.
What karat actually means
Karat expresses how many parts out of 24 are gold. Pure gold is 24 parts out of 24; 18K is 18 parts gold and 6 parts other metals, usually copper, silver, zinc or nickel.
| Karat | Purity | Fineness stamp | Common name |
|---|---|---|---|
| 24K | 99.9% | 999 | Pure gold |
| 22K | 91.7% | 916 | 916 gold |
| 21K | 87.5% | 875 | Common in the Gulf |
| 18K | 75.0% | 750 | 750 gold |
| 14K | 58.3% | 585 | 585 gold |
| 10K | 41.7% | 417 | Minimum in the US |
| 9K | 37.5% | 375 | Minimum in the UK |
The stamps in that table are the conventional hallmark standards you will actually see on jewellery. They are rounded to the trade standard rather than to the exact arithmetic — 22K works out to 91.67%, which would be 917, but is conventionally stamped 916 because a hallmark may not overstate purity. Likewise 14K calculates to 583 but is sold to the 585 standard, since pieces are alloyed slightly above the minimum. The calculator above reports the exact mathematical fineness, so it may differ from the stamp by a point or two.
Do not confuse the karat of gold purity with the carat used for gemstone weight — one carat is 0.2 grams. The words sound identical and mean entirely different things.
What 916 means
916 is the millesimal fineness of 22K gold: 916 parts gold per thousand, which is 22 ÷ 24 = 91.67% rounded down. The stamp is a direct statement of purity and is more precise than the karat number.
It is the most common standard for jewellery across South Asia and the Middle East, favoured because it is noticeably richer in colour than 18K while still hard enough to wear daily. Pure 24K is too soft for most jewellery, which is why it is generally kept as bars and coins.
Choosing a karat for jewellery
- 24K — deepest colour, but soft enough to scratch and bend. Usually held as investment metal rather than worn.
- 22K — rich colour with reasonable durability. The traditional choice in South Asia and the Gulf.
- 18K — noticeably harder, holds stones securely. The standard for fine Western jewellery.
- 14K and below — hard-wearing and affordable, with a paler colour. Common in the US and UK.
Higher karat is not automatically better — it depends on the piece. A ring worn daily and set with stones benefits from 18K; a bangle valued partly as a store of wealth is often 22K.
Alloy content affects more than hardness. Some white gold alloys contain nickel, which a minority of people react to. If you have a known metal sensitivity, ask what the alloy contains before buying.
Weight and price
Gold is weighed in different units depending on where you are, and mixing them up is an expensive mistake:
| Unit | In grams | Used in |
|---|---|---|
| Gram | 1 | Most of the world |
| Tola | 11.6638 | South Asia |
| Troy ounce | 31.1035 | International bullion pricing |
| Kilogram | 1,000 | Bars and bulk trading |
A troy ounce is heavier than the ordinary ounce used for food (28.35 g). Bullion prices are quoted per troy ounce, so converting with the wrong figure introduces about a 10% error. Note also that this calculator holds no gold prices — rates move constantly, so you enter today's figure and it works in any currency.
How much is 14k gold per gram? 10K and 18K gold per gram too
Gold prices are quoted for pure (24K) gold. Lower karats contain less gold, so they are worth less per gram. Multiply today's 24K price per gram by the purity:
Price per gram (karat) = 24K price per gram × purity
| Karat | Purity | If 24K is $100/g | If 24K is $130/g |
|---|---|---|---|
| 24K | 99.9% | $100.00 | $130.00 |
| 22K | 91.7% | $91.70 | $119.21 |
| 21K | 87.5% | $87.50 | $113.75 |
| 18K | 75.0% | $75.00 | $97.50 |
| 14K | 58.3% | $58.30 | $75.79 |
| 10K | 41.7% | $41.70 | $54.21 |
The dollar figures are examples only. Gold prices change every day, so look up today's 24K price and enter it in the Price per gram box above for real numbers.
How much is 14 karat gold worth? (and 10K or 18K)
- Weigh the item in grams (a kitchen scale is fine for a rough idea).
- Multiply by the karat purity to get the grams of pure gold. 20 g of 14K holds 20 × 0.583 = 11.66 g of pure gold.
- Multiply by today's 24K price per gram. That is the melt value.
Buyers usually pay less than melt value — they need to refine it and make a profit. Getting quotes from two or three buyers helps. Jewellery from a known brand may sell for more than its gold content.
How much is 1 gram of gold worth?
One gram of pure 24K gold is worth the day’s spot price divided by 31.1035, because gold is priced per troy ounce and a troy ounce is 31.1035 grams. Every other karat is worth that figure times its purity: 14K is 58.3% of it, 18K is 75% and 10K is 41.7%.
- Gold per gram price to per ounce: multiply by 31.1035. If 14K gold is worth $58 a gram, the worth of 14K gold per ounce is about $1,804.
- Scrap gold price per gram: buyers pay less than this melt value — often 70%–90% of it — to cover refining and profit. Ask for the percentage of melt value before you sell.
- Jewellery price vs gold value: new jewellery costs more than its gold content because of design, labour and retail margin.
This tool does not show live prices. Check today’s 24K price from a bullion dealer or your local market, enter it above, and the calculator works out the value for any karat and weight.
Other ways to use this calculator
Karat conversion plus today's price gives you a full gold value calculator.
- Gold price per gram calculator — enter today's price per gram and the weight to see the value.
- 14K, 10K and 18K gold price per gram calculator — multiply the 24K price by the karat purity — see what gold is worth per gram.
- Gold melt value and scrap gold calculator — the value shown is the melt value; buyers usually pay less.
- Gold weight calculator in grams and tola — switch the unit between grams, tola and troy ounces.
- Gold purity calculator and karat converter — convert 24k to 22k, 18k or any karat by purity.
- Gold fineness — fineness is purity in parts per thousand: 22K is 916, 18K is 750.
- 14k gold price per gram and 10k gold price per gram — multiply today’s 24K price by 0.583 or 0.417; 22K gold price uses 0.917.
- How much is 14k gold worth? — weight in grams × the 14K price per gram.
Related guides
Frequently asked questions
Karat is the proportion of gold out of 24 parts. Pure gold is 24K; 18K is 18 parts gold and 6 parts other metals such as copper, silver or zinc. So 18K is 75% gold. Do not confuse it with the carat used for gemstones, which is a weight of 0.2 grams — the words sound the same but measure completely different things.
Because you are adding alloy, not gold. 100 g of 24K contains 100 g of pure gold. To express that same gold as 22K, which is 91.7% pure, you divide by 0.9167 and get 109.09 g — the original 100 g of gold plus 9.09 g of other metals. The gold content has not changed at all; only the total weight has.
916 is the millesimal fineness of 22K gold — 916 parts gold per thousand, from 22 ÷ 24 = 91.67%. It is the most common jewellery standard across South Asia and the Middle East, chosen because it keeps a rich colour while being hard enough for daily wear. Pure 24K is too soft for most jewellery, which is why it is generally kept as bars and coins.
It depends on the piece rather than the number. 22K gives a richer colour and is traditional in South Asia and the Gulf. 18K is harder, holds stones more securely, and is standard for fine Western jewellery. 14K and below are hard-wearing and affordable but paler. A daily-wear ring benefits from 18K; a bangle held partly as a store of value is often 22K.
Multiply today's 24K gold price per gram by 0.583, because 14K gold is 58.3% pure. If 24K gold is $100 a gram, 14K gold is worth about $58.30 a gram in metal value.
10K gold is 41.7% pure, so a gram is worth about 41.7% of the 24K price per gram. Multiply the weight in grams by 0.417 and by today's 24K price to get its melt value. Buyers usually pay somewhat less.
10K gold is 41.7% pure, so a gram is worth 41.7% of the day’s 24K price per gram. If pure gold is $100 a gram, 10K is worth about $41.70 a gram in gold content. Scrap buyers usually pay somewhat less than that.
Sources and further reading
- British Hallmarking Council — UK hallmarking standards — millesimal fineness stamps and legal minimum standards
- US Federal Trade Commission — Jewellery guides — karat marking rules and the 10K US minimum
- NIST — Units of weight and the troy ounce — troy versus avoirdupois ounce definitions