Weight conversion
Carat to Gram converter
Convert ct to g instantly, choose the displayed precision, and verify the result with the formula and reference table below.
Gram (g)
Rounded for display only; calculations retain full precision.
Rounding and precision rules
- Convr calculates first and rounds the displayed result only once, at the final step.
- The default is a maximum of 6 decimal places; trailing zeros are removed.
- Very small values that would appear as zero, and values of 10¹² or more, use scientific notation.
- Display precision is not measurement uncertainty. For scientific, engineering, or regulated work, retain only the digits justified by the source measurement.
Practical context
Understanding this conversion
The metric carat is used for diamonds and other gemstones. Grams make it easier to compare gemstone mass with ordinary metric weights or calculate the combined mass of several stones.
Since one metric carat is exactly 200 milligrams, it is exactly 0.2 gram. Multiply carats by 0.2 to obtain grams.
Reviewed August 16, 2026.
Calculation
Carat to Gram formula
g = ct × 0.2
Calculations retain full precision and the result is rounded only for display.
Worked example
For 10 ct, the result is 2 g. Substitute 10 ct into the formula to obtain 2 g.
A numerical value expressed in gram is usually smaller than the same measurement expressed in carat, because 1 ct equals 0.2 g.
Carat to Gram reference table
Common values rounded to a maximum of 6 decimal places.
| Carat (ct) | Gram (g) |
|---|---|
| 1 ct | 0.2 g |
| 5 ct | 1 g |
| 10 ct | 2 g |
| 50 ct | 10 g |
| 100 ct | 20 g |
Understanding the units
About Carat and Gram
Carat (ct)
One carat (ct) equals 0.0002 kg, the base relationship used for this weight conversion.
Gram (g)
One gram (g) equals 0.001 kg, the base relationship used for this weight conversion.
When this conversion is useful
Carat to Gram conversion is useful for shipping, recipes, product specifications, laboratory work, and body-weight records. It lets you compare the same mass or weight across documents, tools, or standards that use different units.
Learn with Convr
Conversion guides
Metric vs Imperial Units: A Practical Comparison
Understand how metric, US customary, and Imperial units differ, where each system is used, and how to convert between them reliably.
Read guide →FoundationsSignificant Figures and Rounding in Unit Conversions
Learn when to round conversion results, how significant figures preserve measurement meaning, and why more decimals do not guarantee more accuracy.
Read guide →Answers at a glance
Frequently asked questions
How many grams are in one carat?
One metric carat is defined as exactly 0.2 gram, or 200 milligrams.
Is a gemstone carat the same as gold karat?
No. Carat measures gemstone mass, while karat describes the purity of gold.
How does Convr round Carat to Gram results?
Convr keeps full numeric precision during the calculation and rounds only the displayed result. The default is a maximum of 6 decimal places, with selectable precision on this page.
Can I convert negative or decimal carat values?
Yes. The converter accepts positive, negative, decimal, and scientific-notation values. Negative values are physically meaningful for some scales, such as temperature, but not for every measured quantity.
Keep converting