Carat to Stone Converter
Convert Carat (ct) to Stone (st) instantly. 1 ct = 3.149461e-5 st.
Mass Converter
26 units available
1 ct = 3.149461e-5 st
Formula:
st = ct × 0.0000314946With your value: 1 ct = 3.149461e-5 st
How big is that?
Everyday references on a logarithmic scale, all expressed in carat so you can sanity-check the result.
Other Carat to Stone conversions
Carat to Stone Conversion Table
| Carat (ct) | Stone (st) |
|---|---|
| 0.5 | 1.574730e-5 |
| 1 | 3.149461e-5 |
| 2 | 6.298922e-5 |
| 5 | 0.000157 |
| 10 | 0.000315 |
| 15 | 0.000472 |
| 20 | 0.00063 |
| 25 | 0.000787 |
| 50 | 0.001575 |
| 100 | 0.003149 |
| 250 | 0.007874 |
| 500 | 0.015747 |
| 1000 | 0.031495 |
Stone to Carat Conversion Table
| Stone (st) | Carat (ct) |
|---|---|
| 0.5 | 15,875.73295 |
| 1 | 31,751.4659 |
| 2 | 63,502.9318 |
| 5 | 158,757.3295 |
| 10 | 317,514.659 |
| 15 | 476,271.9885 |
| 20 | 635,029.318 |
| 25 | 793,786.6475 |
| 50 | 1,587,573.295 |
| 100 | 3,175,146.59 |
| 250 | 7,937,866.475 |
| 500 | 15,875,732.95 |
| 1000 | 31,751,465.9 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Carat (ct)
Mass
The metric carat is exactly 200 mg, agreed internationally in 1907.
National Institute of Standards and Technology (US) · Reviewed 2026-07-01
Stone (st)
Mass
Traceable to the kilogram, defined by fixing the Planck constant at 6.626 070 15 × 10⁻³⁴ J·s. Avoirdupois masses derive from the 1959 international pound (0.453 592 37 kg exactly).
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · Reviewed 2026-07-01
How to Convert Carat to Stone
To convert from Carat (ct) to Stone (st), multiply the value by 3.149461e-5.
Formula: st = ct × 0.0000314946
Reverse: ct = st × 31,751.4659
Step-by-Step Example
- Start with your value in Carat. For example: 5 ct
- Multiply by the conversion factor: 5 x 3.149461e-5
- The result is: 0.000157 st
About Carat
The carat equals 200 milligrams and is the standard unit for measuring gemstone weight.
Fun Fact: The word "carat" comes from the carob seed, which was used as a balance weight in ancient gem trading.
Common uses: gemstones, diamonds, jewelry.
About Stone
The stone equals 14 pounds or about 6.35 kg. It is primarily used in the UK and Ireland for expressing body weight.
Fun Fact: The stone varied in weight depending on the commodity being weighed until it was standardized at 14 pounds in 1835.
Common uses: body weight (UK), agriculture.
Frequently Asked Questions
How many Stone are in 1 Carat?
There are exactly 3.149461e-5 Stone in 1 Carat. This means the conversion factor from Carat to Stone is 3.149461e-5.
What is the formula to convert Carat to Stone?
The formula to convert Carat to Stone is: st = ct × 0.0000314946. For example, to convert 10 Carat to Stone, you would multiply 10 by 3.149461e-5.
What is a Carat?
The carat equals 200 milligrams and is the standard unit for measuring gemstone weight.
What is a Stone?
The stone equals 14 pounds or about 6.35 kg. It is primarily used in the UK and Ireland for expressing body weight.
What are the common uses of Carat?
The Carat is commonly used in gemstones, diamonds, jewelry.
Related Mass Conversions
Cite this page
UnitConvertLab. (2026). Carat to Stone converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/carat-to-stone