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Gold Karat & Purity Calculator: Convert Karat to Gold Purity and Value
Gold purity tells you how much actual gold is contained in a piece of jewellery. Gold is commonly described using karats (K), while purity is also expressed as a percentage or a fineness number such as 916 or 750.
For example, 22K gold is approximately 91.6% pure gold, which is why it's commonly referred to as 916 gold. The calculator above lets you convert between karat, purity percentage, and estimated value per gram using the applicable current gold rate.
What does gold karat mean?
Karat is a measure of the proportion of pure gold in a gold alloy. Pure gold is represented as 24K. The basic relationship is:
Gold Purity % = Karat ÷ 24 × 100
For example: 22 ÷ 24 × 100 = 91.67% — commonly represented as 91.6% purity or 916 fineness.
Gold jewellery is often mixed with other metals to make it harder and more suitable for everyday use. As a result, jewellery is commonly sold in purities such as 22K, 18K, and 14K rather than 24K.
Gold karat and purity chart
Here's a quick reference for commonly used gold purities:
| Gold karat | Approx. purity | Common fineness |
|---|---|---|
| 24K | 99.9% | 999 |
| 22K | 91.6% | 916 |
| 18K | 75.0% | 750 |
| 14K | 58.5% | 585 |
The percentages shown are commonly used commercial purity representations. Actual hallmark specifications and testing results should be checked for a specific piece of jewellery.
How to convert karat to gold purity
The simplest formula is:
Purity % = (Karat ÷ 24) × 100
For example, to calculate the purity of 18K gold: 18 ÷ 24 × 100 = 75% — therefore 18K gold = 75% pure gold. Similarly:
- 24K ≈ 99.9% gold
- 22K ≈ 91.6% gold
- 18K = 75% gold
- 14K ≈ 58.5% gold
Use the calculator above to quickly convert between these values without doing the calculation manually.
What is 916 gold?
916 gold refers to gold with approximately 91.6% purity, commonly associated with 22K gold. The number 916 comes from the fineness system: 916 parts gold per 1,000 parts of the alloy. In other words, approximately 91.6% of the material is gold, while the remaining portion consists of other metals used to create an alloy.
22K gold is widely used for jewellery because it provides a balance between relatively high gold content and greater durability than very soft, near-pure gold.
What is 750 gold?
750 gold refers to gold with 750 parts pure gold per 1,000 parts of the alloy — 750 ÷ 1,000 = 75%. Therefore, 750 gold = 75% purity = 18K gold. 18K gold is commonly used for jewellery where additional strength and design flexibility are desirable.
What is 585 gold?
585 gold contains approximately 58.5% pure gold, commonly associated with 14K gold = 58.5% purity. Because it contains a larger proportion of other metals than 18K or 22K gold, 14K gold can be harder and more durable for certain jewellery applications.
What is 24K gold?
24K gold represents gold in a very high-purity form. Commercially, 24K gold is commonly represented as approximately 99.9% pure gold, often described as 999 gold. Because pure gold is relatively soft, 24K gold is less commonly used for everyday jewellery than lower-karat alloys — it's commonly encountered in forms such as investment bars, coins, and other high-purity gold products.
What is the difference between karat and purity?
Karat and purity describe essentially the same underlying concept using different measurement systems. Karat expresses gold purity out of 24 parts. Purity percentage expresses the proportion of gold as a percentage. For example: 22K = 22/24 ≈ 91.6% gold, 18K = 18/24 = 75% gold. So if a jeweller says a piece is 18K, approximately 75% of its metal content is gold.
How is gold value per gram calculated?
The value of gold per gram depends on both the applicable gold rate and the purity of the gold. A simplified way to calculate the value of pure gold content is:
Gold Value per Gram = 24K Gold Rate × Purity
For example, if the 24K gold rate is ₹14,500 per gram and you want to estimate the gold component of 22K gold: ₹14,500 × 91.6% ≈ ₹13,282 per gram. The actual rate used by a jeweller can differ because of pricing methodology, market conditions, and other transaction-specific factors — the calculator above provides an indicative value per gram based on today's rate.
Check today's applicable gold rate
See 24K, 22K, and 18K prices per gram right now, before converting a purity to a value.
Why is 22K gold cheaper per gram than 24K gold?
22K gold contains less pure gold than 24K gold — approximately 24K → 99.9% gold, 22K → 91.6% gold. So when the underlying 24K gold rate is used as the reference, the intrinsic gold component of one gram of 22K gold is lower than that of one gram of 24K gold.
However, the final price of jewellery isn't determined by gold purity alone. Jewellery pricing can also include:
- Making charges
- Wastage
- Gemstones or other materials
- Taxes
- Brand premiums
- Other applicable charges
Why does gold purity matter when buying jewellery?
Purity affects both the amount of gold contained in the jewellery and its value. Consider two jewellery pieces weighing 10 grams each:
| 22K gold | 18K gold | |
|---|---|---|
| Weight | 10g | 10g |
| Approx. gold content | 91.6% | 75% |
| Approx. pure gold content | 9.16g | 7.5g |
Even though both pieces weigh 10 grams, the 22K piece contains more gold. This is why you should always consider purity together with weight when comparing gold jewellery.
Does higher karat always mean better gold?
Not necessarily. Higher karat means a higher proportion of gold, but the best choice depends on how you intend to use the jewellery.
24K gold
- Very high gold purity
- Softer than lower-karat alloys
- Commonly used for investment gold rather than everyday jewellery
22K gold
- High gold content
- Commonly used in traditional jewellery
- A popular choice for many Indian jewellery purchases
18K gold
- 75% gold
- More alloyed metals than 22K
- Often suitable for detailed and contemporary jewellery designs
14K gold
- Approximately 58.5% gold
- Higher proportion of alloy metals
- Often more durable for everyday wear
Choosing gold should involve more than simply selecting the highest karat.
Still deciding between 24K, 22K, and 18K?
24K vs 22K vs 18K Gold: Which Purity Should You Buy? — how to pick based on what you're actually buying gold for.
How to check the purity of gold jewellery
If you already own gold jewellery and want to know its purity, look for relevant hallmark information on the piece. In India, hallmarked jewellery can carry information indicating its purity. You may also encounter identifiers such as:
- 22K916
- 18K750
- 14K585
These numbers correspond to the approximate fineness of the gold alloy. For a purchase or resale transaction, don't rely solely on appearance — ask the jeweller to provide the purity information and, where necessary, have the gold tested according to the applicable process.
Gold purity and jewellery pricing
Gold purity is only one component of the final jewellery price. A simplified jewellery price calculation can look like:
Gold Value + Making Charges + Wastage + Applicable Taxes = Final Price
This means two jewellery pieces with the same weight can have very different prices. For example, a 10-gram 22K necklace and a 10-gram 22K bracelet contain approximately the same amount of gold, but their final prices may differ because of design, making charges, and other costs.
Buying jewellery? Get the full cost breakdown
See gold value, making charges, and GST laid out line by line — not just the gold rate.
Gold purity when selling old jewellery
Purity is particularly important when selling old gold. A jeweller may verify the purity of your jewellery before calculating the amount they're willing to pay — if you believe a piece is 22K but its verified purity is lower, the calculated gold value may also be lower. The resale calculation can be broadly represented as:
Net Gold Weight × Applicable Rate × Purity − Applicable Deductions
Making charges paid when you originally purchased the jewellery generally shouldn't be assumed to be recoverable when you sell it.
Selling old jewellery?
Estimate its resale value before comparing buyback offers, using its verified purity and today's rate.
Gold karat vs. gold fineness
You may see gold purity expressed in three different ways:
- Karat: 22K
- Percentage: 91.6%
- Fineness: 916
These refer to the same general purity level. For example: 22K ≈ 91.6% ≈ 916 fineness. Similarly: 18K = 75% = 750 fineness. Understanding all three formats makes it easier to compare jewellery quotations, hallmarks, and gold products.
Quick gold purity conversion table
| Karat | Purity | Fineness |
|---|---|---|
| 24K | ~99.9% | 999 |
| 23K | ~95.8% | 958 |
| 22K | ~91.6% | 916 |
| 21K | ~87.5% | 875 |
| 20K | ~83.3% | 833 |
| 18K | 75.0% | 750 |
| 14K | ~58.5% | 585 |
| 10K | ~41.7% | 417 |
| 9K | 37.5% | 375 |
The commonly used jewellery purities can vary by market. This table is provided as a mathematical reference — always check the hallmark and applicable standards for a specific product.
Check your gold purity before you buy or sell
Understanding karat and purity can help you make better decisions when buying, comparing, or selling gold. Remember the basic conversions:
- 24K ≈ 99.9% ≈ 999
- 22K ≈ 91.6% ≈ 916
- 18K = 75% = 750
- 14K ≈ 58.5% ≈ 585
Use the calculator above to convert between karat and purity and estimate the corresponding value per gram using the applicable gold rate. If you're buying jewellery, use the Jewellery Cost Calculator to estimate your complete jewellery cost. If you're selling old jewellery, use the Gold Resale Calculator to estimate its potential resale value before comparing a jeweller's offer.
Disclaimer: Gold rates and jewellery prices can change. Values shown by this calculator are estimates for informational purposes and may differ from actual market, retail, or resale prices. Purity should be verified using the applicable hallmarking or testing process. This calculator does not constitute a guarantee, valuation certificate, or financial advice.