Gold Karat Calculator (Karat to Fineness and Purity %)
Check gold purity and fineness stamps instantly
The Gold Karat Calculator helps you understand gold purity in seconds. Pick a karat like 14K, 18K, or 22K and you will see the purity percentage and the matching fineness stamp like 585, 750, or 916. You can also enter a fineness stamp to estimate the karat. Use this tool when you buy jewelry, check a hallmark, or compare 24K vs 18K vs 14K.
Want to go one step further? Turn on the weight option to see how much of your item is pure gold and how much is alloy. It works for grams, tola, and ounces. Scroll down to see the purity chart first. Then run your numbers in the calculator.
According to global standards, 24K gold is 99.9% pure, while 14K gold contains exactly 58.5% pure gold.
- Updated Feb 10, 2026
Live Gold Price Today by Weight and Karat
Gold prices change every day. Sometimes they change every minute. This live gold price shows the current spot rate so you can calculate with real numbers. You can check the gold price per gram, per troy ounce, or per tola. This helps when you value 14K, 18K, 21K, or 22K gold. Always start with the current price before you calculate gold value, melt value, or scrap payout.
This works for the USA market and global users. Prices update automatically. You do not need to refresh the page.
Calculate Gold Purity & Decode Hallmarks
Ready to check your jewelry? Select your calculation mode below to convert Karats to Purity percentage or decode a Fineness stamp (like 585 or 750). You can also toggle the weight option to uncover the exact amount of pure gold hidden inside your item.
Gold Karat Calculator
Result details will appear here.
How to Read Your Gold Karat Calculator Results?
Understanding your results is easy. The calculator shows you three key numbers. First is the purity percentage. This tells you how much real gold you have. Next is the fineness. This number matches the stamp on your jewelry. Finally, the stamp meaning confirms the karat value. Use these numbers to verify your gold items quickly.
What Does Purity Percentage Mean?
Purity percentage reveals the actual gold content in your metal. It simply separates the gold from the alloy. For instance, 75% purity means three-quarters of the item is gold. Higher numbers equal more worth. This helps you value the item instantly. Now, compare this to the fineness stamp.
What is Gold Fineness?
Gold fineness measures purity in parts per 1000. It uses a 1000-point scale instead of a percentage. For example, a 750 stamp means 750 parts are gold. This is the global standard for jewelry. It offers more precision than karats. Next, check how these numbers match real hallmarks.
What Does the Stamp Meaning Show?
The stamp meaning links your jewelry mark to a specific karat value. Real gold usually carries a hallmark number. This result identifies that number for you. If you see 585 on a ring, the tool confirms it is 14K. This proves the item is authentic. Look at these sample results next.
Sample Calculation Outputs
Here are two common results you might see. First, enter 14K into the tool. You get 58.5% purity and a 585 stamp. Alternatively, type 750 fineness. This result equals 18K gold and 75.0% purity. These numbers help you verify value quickly. Ready to try? Here is how it works.
Test the Calculator With Real Examples
Use the examples below to test the calculator. Enter the values exactly as shown. You can change them later to match your own jewelry.
Example 1: Decode a “585” Stamp
Use this to test: Fineness to Karat Mode
- Mode: Fineness to Karat
- Fineness Input: 585
What you should see:
- Calculated Karat is 14K.
- Purity percentage is 58.5%.
- Stamp meaning confirms the standard 14K mark.
Example 2: Check Weight for 18K Gold
Use this to test: Karat to Purity Mode with Weight
- Mode: Karat to Purity
- Select Karat: 18K
- Weight Checkbox: Checked (On)
- Weight: 10 grams
What you should see:
- Fineness result is 750.
- Pure gold weight equals 7.50 g.
- Alloy weight equals 2.50 g.
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Try calculatorHow to Use the Gold Karat Calculator?
Follow these simple steps to check your gold purity in seconds.
Choose a Mode
Start by picking the correct option. Use Karat to Purity if you know the karat value (like 14K). Use Fineness to Karat if you only see a stamp number on your jewelry.
Select Karat or Enter Fineness
Pick a standard karat like 10K, 14K, or 18K from the dropdown menu. Alternatively, type the specific stamp number (like 585 or 916) directly into the input box.
Turn on Weight (Optional)
Toggle the weight switch if you want a pure gold split. Enter your item's total weight in grams, tolas, or ounces. This calculates exactly how much pure gold is inside the alloy.
Click Calculate
Press the Calculate button. The tool processes your inputs instantly without reloading the page.
Read the Results
Check the results bar. You will see the purity percentage and the exact fineness value. The tool also explains the stamp meaning to help you verify your item.
Quick Formula Used
Fineness Formula: Fineness = Round((Karat ÷ 24) × 1000)
Purity Percentage Formula: Purity % = Fineness ÷ 10
Pure Gold Weight Formula:
Pure Gold = Total Weight × (Fineness ÷ 1000)
Why This Process Is Accurate
- Standard Fineness Scale: We use the 1000-part scale. This is the global standard for trading.
- Real-World Rounding: The math accounts for standard stamps. For example, 14K calculates to 585, not just a raw decimal.
- Exact Weight Split: We apply purity to the total weight first. This separates the gold from the alloy correctly.
Try It Yourself
- Select Karat to Purity mode.
- Choose 18K from the list.
- Check the result. You will see 750 fineness and 75% purity.
- Now switch modes. Enter 916 to see it convert back to 22K.
Gold Karat Formula and Variables (Complete Breakdown)
This section explains how the calculator works. It shows the math behind karats, fineness, and purity. You see exactly how we convert numbers. This helps you understand the results. It also lets you check the math yourself.
Karat and Fineness Formulas Explained
These formulas power the calculator. You use them to switch between karats and stamps. The tool does this instantly.
Karat to Fineness Formula Fineness = Round((Karat ÷ 24) × 1000)
Fineness to Karat Formula
Karat = (Fineness ÷ 1000) × 24
Purity Percentage Formula
Purity % = Fineness ÷ 10
Variable 1: Karat (K)
Karat measures gold purity out of 24 parts. 24K is pure gold. 12K is half gold. This is the common system in the USA.
Variable 2: Fineness
Fineness measures purity out of 1000 parts. It is more precise than karat. Jewelers use this for stamps. For example, 585 means 585 parts are gold.
Variable 3: Purity Percentage
This is the easiest number to understand. It tells you the gold content as a percent. We find it by dividing fineness by 10.
Weight Helper Formulas
If you enter weight, we calculate the pure gold inside. This shows the real value of the item.
Pure Gold Formula Pure Gold = Total Weight × (Fineness ÷ 1000)
Alloy Formula Alloy = Total Weight − Pure Gold
Variable 4: Total Weight & Unit
This is the weight of your jewelry item. You can use grams, tola, or ounces. The calculator splits this total into pure gold and alloy metals.
Example Calculation You Can Test
Use this exact input to test the calculator.
Given:
- Karat: 18K
- Weight: 10 grams
Calculation:
Find Fineness:
(18 ÷ 24) × 1000 = 750
Find Purity %:
750 ÷ 10 = 75.0%
Find Pure Gold:
10 grams × 0.750 = 7.50 grams
Find Alloy:
10 grams − 7.50 grams = 2.50 grams
Result:
- 750 Fineness and 7.50 g Pure Gold
You should see the same number in the calculator result panel.
Why This Formula Matters
This formula reveals the true content of your jewelry. It separates the valuable gold from the cheap alloy. Many buyers assume 18K gold is solid gold. It is actually 25% alloy. Knowing this split helps you estimate value accurately. It also helps you verify that the stamp matches the karat claim. You can now trade or buy with confidence.
Gold Purity Benchmarks and Stamp Guide
Your gold karat result is more than just a number. It defines the actual value and durability of your jewelry. High karats like 24K are soft and expensive. Lower karats like 10K are hard and affordable. Markets in the USA and Europe use specific stamps to mark these grades. Here is a quick guide to help you read your stamp and judge the quality.
| Fineness Range | Karat Label | Purity Percentage | Common Usage | Stamp Meaning |
|---|---|---|---|---|
| 999 – 995 | 24K Gold | 99.9% Pure Gold. | Bars, Coins, Investments. | Softest form. Stamp 999. |
| 916 | 22K Gold | 91.6% Pure Gold. | Indian & Asian Jewelry. | Rich yellow. Stamp 916. |
| 750 | 18K Gold | 75.0% Pure Gold. | Fine Jewelry & Watches. | Ideal balance. Stamp 750. |
| 585 | 14K Gold | 58.5% Pure Gold. | US Standard Daily Wear. | Very durable. Stamp 585. |
| 417 | 10K Gold | 41.7% Pure Gold. | Budget & Class Rings. | Hardest alloy. Stamp 417. |
Important: Always verify the stamp on your item. If a piece is marked "GP" or "HGE" next to the number, it is plated, not solid gold.
How to Read This Table With the Calculator
First, run a calculation above using your jewelry’s stamp or karat. Note the Fineness result. Now compare:
Now compare:
- Your Result vs. Table Range: Does your number match a standard row?
- Stamp vs. Karat: Does your stamp (e.g., 585) match the correct Karat (14K)?
- Usage Check: Is your soft 24K gold ring actually meant for daily wear?
This comparison shows you the quality of your gold. It also helps you spot fake or under-karated items.
What This Means For You
If your result matches the 22K or 24K range, your item is high value but very soft. You should treat it with care. If it falls in the 14K or 10K range, it contains more alloy. This makes it durable and safe for everyday use. Always use this table to verify that a seller’s claim matches the actual stamp on the metal.
Quick Example Using the Karat Mode
Inputs:
- Mode: Karat to Purity
- Selection: 18K
Results you will see:
- Purity: 75.0%
- Fineness: 750
Now check the table row for “750”. It confirms this is the standard for Fine Jewelry & Watches.
Expert Insights for Smart Gold Decisions
Gold purity can be confusing. Use these expert tips to verify what you own and avoid overpaying.
Match the Stamp Before You Price
Always look for the hallmark stamp first. A seller might claim a ring is “Gold,” but the stamp tells the real story. If you see 585, it is only 58.5% gold (14K). If you see 916, it is 91.6% gold (22K). Use this calculator to decode the number. This ensures you never pay a 24K price for 14K quality.
Use the Weight Option for Real Value
Karat purity is only half the equation. The weight matters just as much. A heavy 14K chain often contains more actual gold than a tiny 24K coin. Turn on the weight toggle in the calculator. It separates the pure gold from the alloy. This reveals the true amount of precious metal you actually hold.
Compare Karats Carefully in Listings
Online listings often use confusing terms. You might see “Solid Gold” used for both 18K and 10K items. Use the tool to compare them side-by-side. Remember that 24K is soft and bends easily. 14K is hard and resists scratches. Choose the right karat for your lifestyle, not just the highest number.
Watch Out for Plated Markings
A stamp saying “14K” is valuable. A stamp saying “14K GP” or “HGE” is not. These letters mean Gold Plated. The item is actually copper or brass with a tiny layer of gold. This calculator is designed for solid gold. Plated items have almost zero recoverable gold weight. Always check for these extra letters to avoid a costly mistake.
Use these tools to double-check your numbers before selling or buying.
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Try calculatorCommon Gold Calculation Mistakes
Avoid these simple errors to ensure you get accurate results every time.
- Mixing Up Karat with Carat Do not confuse these two terms. Karat (K) measures the purity of gold. Carat (ct) measures the weight of diamonds and gemstones. They refer to completely different things.
- Assuming 24K is 100% Pure 24K gold is technically 99.9% pure. It is impossible to remove every single impurity atom. The market treats it as pure. However, the math uses 0.999, not 1.000.
- Reading Stamps Wrong Be careful with fineness numbers. A 585 stamp means 58.5% gold. It does not mean 85.5%. Always divide the stamp number by 10 to get the correct percentage.
- Ignoring Alloy Weight Remember that karat gold is mixed with other metals. An 18K ring is only 75% gold. The remaining 25% is copper or silver. If you sell it, you only get paid for the pure gold weight. Do not expect payment for the full weight of the item.
Frequently Asked Questions (FAQs)
What does 585 mean on gold?
The number 585 indicates that the gold purity is 58.5%. This is the standard hallmark for 14K gold. It means 585 parts out of 1000 are pure gold. The rest is alloy metal added for strength. You will find this stamp on most durable jewelry sold in the US and Europe.
Use the calculator to convert 585 back to karat. This confirms the item is authentic 14K gold.
What does 750 mean on gold?
The stamp 750 means the item is 75.0% pure gold. This is the international hallmark for 18K gold. It signifies that 750 parts out of 1000 are gold, while the remaining 250 parts are alloy. This purity level balances rich color with strength, making it ideal for fine jewelry and watches.
Is 999 the same as 24K?
Yes, 999 is the standard fineness stamp for 24K gold. It represents a purity of 99.9%, which is the highest practical purity for investment-grade gold bars and coins. While technically “pure” gold would be 1000, 999 is the globally accepted standard for fine gold trading and valuation.
How do I convert karat to fineness?
To convert karat to fineness, divide the karat value by 24 and multiply by 1000. For example, for 18K gold:
(18 ÷ 24) × 1000 = 750
This gives you the standard 3-digit stamp found on jewelry. Our calculator handles this instantly using the standard rounding rules used by jewelers.
What is the difference between 14K and 18K?
The main difference is purity and hardness. 18K gold is 75% pure, making it brighter yellow and more expensive. 14K gold is only 58.5% pure. This makes 14K harder, more durable, and more affordable. Choose 18K for fine jewelry and 14K for items you wear every day.
In short: 18K is for luxury; 14K is for durability.
What is gold fineness?
Gold fineness measures purity on a scale of 1000 parts. Unlike karats, which use a scale of 24, fineness uses a precise 3-digit number. For example, 750 fineness means the item contains 750 parts gold and 250 parts alloy. This is the global standard for stamping jewelry and bullion.
Jewelers prefer fineness because it is more accurate than the karat system. It allows for exact valuation of gold content in investment bars, coins, and scrap metal markets worldwide.
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