A metric carat is exactly 200 milligrams.
Carats to Ronnagrams Converter — ct to Rg
Convert Carat (ct) to Ronnagram (Rg) using the exact conversion factor (1 carat = 2e-28 ronnagram). See the formula, worked examples, and conversion table.
Carats to Ronnagrams converter
Converter
Mass/Weight Converter
Convert SI mass, imperial weight, jewelry, atomic, and astronomy mass units.
Context values
Some unit families need one extra value for a physically accurate result.
Ronnagram is 1e+27 gram units.
Result = input x 0.0002 / 1e+24.
Mass uses the kilogram as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Carats to Ronnagrams
Weight conversions between Carat and Ronnagram come up constantly in everyday commerce, shipping, and cooking, since US packaging is usually labeled in pounds while most of the rest of the world uses kilograms. Specifically: A metric carat is exactly 200 milligrams, and ronnagram is 1e+27 gram units.
Formula
ronnagrams = carats × 2e-28
This factor comes from each unit's defined relationship to the category's base unit: 1 carat equals 0.0002 base units, and 1 ronnagram equals 1e+24 base units, so dividing one by the other gives the direct carat-to-ronnagram factor of 2e-28.
Simple example
1 ct × 2e-28 = 2e-28 Rg
1 carat = 2e-28 ronnagrams.
Real-world example
50 ct × 2e-28 = 1e-26 Rg
50 carats = 1e-26 ronnagrams.
Conversion table
| Carat (ct) | Ronnagram (Rg) |
|---|---|
| 1 ct | 2e-28 Rg |
| 5 ct | 1e-27 Rg |
| 10 ct | 2e-27 Rg |
| 25 ct | 5e-27 Rg |
| 50 ct | 1e-26 Rg |
| 100 ct | 2e-26 Rg |
Reverse conversion: Ronnagram to Carat
2e-28 Rg × 5e+27 = 1 ct
2e-28 ronnagrams = 1 carats.
carats = ronnagrams × 5e+27
For a page dedicated to this direction, see Ronnagram to Carat.
Understanding the Carat (ct)
A metric carat is exactly 200 milligrams.
Understanding the Ronnagram (Rg)
Ronnagram is 1e+27 gram units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many ronnagrams are in 1 carat?
1 carat equals 2e-28 ronnagrams, using the exact defined conversion factor rather than an estimate.
How do I convert carat to ronnagram?
Multiply the carat value by 2e-28. The converter above does this instantly to whatever precision you set.
How do I convert ronnagram back to carat?
Use the reverse factor: 1 ronnagram equals 5e+27 carats. You can also use the swap control in the converter above to flip the direction instantly.
What is a carat?
Carat (ct) is a unit of mass/weight.
What is a ronnagram?
Ronnagram (Rg) is a unit of mass/weight.
Is the carat to ronnagram conversion exact?
Yes. Both carat and ronnagram are defined by fixed standards rather than physical artifacts, so the factor of 2e-28 used above is exact to as many digits as you choose to display.