Convert weight and mass units — kilograms, pounds, grams, ounces, tons, carats and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 ct | 3.14946e-08 st | |
| 0.01 ct | 3.14946e-07 st | |
| 0.1 ct | 3.14946e-06 st | |
| 1 ct | 3.14946e-05 st | |
| 5 ct | 0.000157473 st | |
| 10 ct | 0.000314946 st | |
| 50 ct | 0.00157473 st | |
| 100 ct | 0.00314946 st | |
| 1000 ct | 0.0314946 st |
The Milligram (mg) and the Gram (g) are both units of weight & mass. Converting between them is straightforward using the formula above.
Formula: 1 ct = 0.00003149462 st
This converter uses internationally recognized conversion factors. All calculations are performed client-side in your browser — no data is sent to any server.
| Carat (ct) | Stone (st) | Real-world context |
|---|---|---|
| 1 ct | 3.1495e-05 st | solitaire diamond |
| 1000 ct | 0.03149462 st | |
| 1,000,000 ct | 31.4946247 st | |
| 1.0000e+09 ct | 31494.6247 st | |
| 1.0000e+12 ct | 31,494,625 st |
1 carat (ct) equals exactly 3.1495e-05 stone (st). Use the formula: ct × 3.1495e-05 = st.
To convert carats to stone, multiply your value in carats by 3.1495e-05. For example, 5 ct × 3.1495e-05 = 0.00015747 st.
100 carats = 0.00314946 stone. Calculation: 100 × 3.1495e-05 = 0.00314946.
To convert stone back to carats, divide by 3.1495e-05 (or multiply by 31751.45). Example: 10 st ÷ 3.1495e-05 = 317514.5 ct.
Yes. This converter uses the internationally recognised exact conversion factor: 1 ct = 3.1495e-05 st. All calculations are performed in your browser with no rounding until display.
10 carats = 0.00031495 stone. Simply multiply by 3.1495e-05.
Converting carats to stone is commonly needed for jewellery valuation, gemstone trading, precious metal buying and selling, and hallmarking compliance where one system uses ct and another uses st.
The metric carat (ct) is the unit of mass used worldwide for gemstones and pearls, equal to exactly 200 milligrams (0.2 g). It is distinct from "karat" (K), the measure of gold purity (24K = 100% gold). A 1-carat diamond weighs exactly 0.2 g; the famous 45.52-carat Hope Diamond weighs approximately 9.1 g.
The stone (st) is a British imperial unit of mass equal to exactly 14 avoirdupois pounds or 6.35029318 kilograms. Used almost exclusively in the United Kingdom and Ireland for human body weight, it has no role in scientific, commercial, or international contexts. The stone is not an SI unit and was removed from official UK trade measurement in 1985, though it remains deeply embedded in everyday British culture.
The word "carat" derives from Greek keration (κεράτιον), meaning carob pod. Carob seeds were believed to have remarkably uniform weight and were used as counterweights for balancing precious stones. The carat value varied across countries (0.187–0.216 g) until the Fourth General Conference on Weights and Measures standardised the metric carat at exactly 200 mg in 1907. Most countries adopted the metric carat between 1914 and 1930.
Interesting fact: The largest gem-quality diamond ever found, the Cullinan Diamond (1905), weighed 3,106.75 carats (621.35 g) before being cut into 9 major and 96 minor stones, two of which are in the British Crown Jewels.
One of the oldest English weight units, the stone was referenced as early as the 13th century. Historically its value varied by commodity (8 lb for meat, 12 lb for hemp, 14 lb for wool, 16 lb for glass). King Edward III standardised the wool stone at 14 pounds in 1350, which became the universal English standard. The Weights and Measures Act 1835 formally defined the stone as 14 lb. EU harmonisation abolished the stone for trade in 1985.
Interesting fact: The world record heaviest person weighed 635 kg — exactly 100 stone, illustrating how the stone unit provides digestible reference points for large body weights. British people typically express their weight as, for example, "11 stone 4 pounds."