How to Convert Carats to Grams (ct to g)
Weight units matter at the wet market, where older stalls and Chinese medical halls still quote prices per kati or tael, and when following American recipes in ounces and pounds. This guide shows how to convert carats into grams by hand, with examples and a quick-reference table.
The conversion
To convert carats to grams, multiply the value by 0.2. To go the other way, divide by the same number (or multiply by 5). For a quick estimate, multiply by about 0.2.
Grams = carats × 0.2
Worked examples
- 3 ct = 0.6 g
- 12.5 ct = 2.5 g
- 75 ct = 15 g
Carats to Grams table
| Carats | Grams |
|---|---|
| 1 ct | 0.2 g |
| 2 ct | 0.4 g |
| 5 ct | 1 g |
| 10 ct | 2 g |
| 20 ct | 4 g |
| 25 ct | 5 g |
| 50 ct | 10 g |
| 100 ct | 20 g |
| 250 ct | 50 g |
| 500 ct | 100 g |
| 1,000 ct | 200 g |
Common questions
Is ct to g exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Grams to Carats converter.
Mistakes to avoid
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Background
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
For any value, use the Carats to Grams Converter or browse all weight converters.
Run your own numbers: Carats to Grams Converter