Convert Carat (metric) to Stone (US)
Convert carats (metric) to stones (us) instantly. 1 carat (metric) = 3.527396e-5 stone (us) — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Stone (US) to Carat (metric) converter for the reverse conversion.
Units explained
Carat (metric)
The metric carat (ct) equals exactly 200 milligrams (0.0002 kg).
From Arabic 'qirat' and Greek 'keration', the carob seed once used as a counterweight.
The worldwide standard for gemstone and diamond mass.
The metric carat was fixed at 200 mg internationally in 1907.
Stone (US)
A less common US definition of the stone, about 5.67 kilograms.
A variant stone weight used in some historical US trade.
Rare; appears mainly in historical or specialized contexts.
Derived from older English stone weights that varied by commodity.
Carat (metric) to Stone (US) conversion formula
The relationship between carats (metric) and stones (us):
To convert carats (metric) to stones (us), multiply the value in carats (metric) by 3.527396e-5. To reverse, multiply stones (us) by 28349.523125.
How to use this converter
Type a value into the calculator. The result in stones (us) updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Stone (US) to Carat (metric) converter for the reverse direction.
Step-by-step: convert carats (metric) to stones (us)
- Write down the value in carats (metric) (ct).
- Multiply that value by the factor 3.527396e-5.
- The product is the equivalent value in stones (us) (st).
- To reverse, multiply the stone (us) value by 28349.523125.
Worked examples
Example 1 — Convert 1 ct to st:
1 × 3.527396e-5 = 3.527396e-5 st
Example 2 — Convert 100 ct to st:
100 × 3.527396e-5 = 0.0035273962 st
Real-world example — Quarter-meter measurement reference
A 250,000-carat (metric) length equals 0.25 stones (us) — useful for comparing supply-chain spec sheets where some lengths are quoted in the smaller unit and some in the larger.
250000 ct × 3.527396e-5 = 8.8184904874 st
Real-world example — From microscopic to macroscopic
A million carats (metric) equals exactly one stone (us). This kind of conversion appears in microfluidics, where total channel length is given in stones (us) but feature widths are in carats (metric).
1000000 ct × 3.527396e-5 = 35.2739619496 st
Real-world example — Macro-scale buildup
A million carats (metric) equals exactly one stone (us) — the conversion that bridges microscale features and macroscale objects in microfluidic, biomedical, and semiconductor packaging design.
1000000 ct × 3.527396e-5 = 35.2739619496 st
Carat (metric) to Stone (US) conversion table
Standard reference values for converting carats (metric) to stones (us):
| Carat (metric) [ct] | Stone (US) [st] |
|---|---|
| 0.01 | 3.527396e-7 |
| 0.1 | 3.527396e-6 |
| 1 | 3.527396e-5 |
| 2 | 7.054792e-5 |
| 3 | 0.0001058219 |
| 4 | 0.0001410958 |
| 5 | 0.0001763698 |
| 10 | 0.0003527396 |
| 20 | 0.0007054792 |
| 30 | 0.0010582189 |
| 40 | 0.0014109585 |
| 50 | 0.0017636981 |
| 100 | 0.0035273962 |
| 500 | 0.017636981 |
| 1000 | 0.0352739619 |
Frequently asked questions
How many stones (us) is 1 carat (metric)?
How do I convert carats (metric) to stones (us)?
How do I convert stones (us) back to carats (metric)?
How many stones (us) is 100 carats (metric)?
Popular weight unit conversions
Convert Carat (metric) to other weight units
Show all Carat (metric) conversions
Metric / SI (18 units)
Avoirdupois (15 units)
Troy & Apothecary (9 units)
Indian / South Asian (6 units)
Scientific / Atomic (9 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Sources & references
Conversion factor (1 ct = 3.527396e-5 st) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.