The carat
The metric carat equals exactly 0.2 grams (200 mg). It is the standard unit for weighing gemstones and pearls worldwide, standardized internationally in 1907 to replace regionally varying carat definitions.
Carats to Grams Converter
1 ct = 0.2 g (carat → gram)
1 ct = 0.2 g
1 carat equals 0.2 grams. To convert carats to grams, multiply the carat value by 0.2. For quick reference: 1 ct = 0.2 g, 5 ct = 1 g, 10 ct = 2 g, 100 ct = 20 g.
Formula
Grams = Carats × 0.2Quick
How to convert carats to grams
Take your value
Start with your value in carats.
Multiply by 0.2
Multiply the carat value by 0.2. This is the exact conversion factor from carats to grams.
Read the result
The product is your value in grams. For example, 5 ct × 0.2 = 1 g.
Conversion formula
The exact factor from carats to grams is 0.2.
Grams = Carats × 0.2
Carats to Grams conversion table
Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.
| Carats (ct) | Grams (g) |
|---|---|
| 0.1 ct | 0.02 g |
| 0.25 ct | 0.05 g |
| 0.5 ct | 0.1 g |
| 1 ct | 0.2 g |
| 1.5 ct | 0.3 g |
| 2 ct | 0.4 g |
| 2.5 ct | 0.5 g |
| 3 ct | 0.6 g |
| 4 ct | 0.8 g |
| 5 ct | 1 g |
| 6 ct | 1.2 g |
| 7 ct | 1.4 g |
| 8 ct | 1.6 g |
| 9 ct | 1.8 g |
| 10 ct | 2 g |
| 12 ct | 2.4 g |
| 15 ct | 3 g |
| 18 ct | 3.6 g |
| 20 ct | 4 g |
| 25 ct | 5 g |
| 30 ct | 6 g |
| 35 ct | 7 g |
| 40 ct | 8 g |
| 45 ct | 9 g |
| 50 ct | 10 g |
| 60 ct | 12 g |
| 70 ct | 14 g |
| 75 ct | 15 g |
| 80 ct | 16 g |
| 90 ct | 18 g |
| 100 ct | 20 g |
| 120 ct | 24 g |
| 125 ct | 25 g |
| 150 ct | 30 g |
| 175 ct | 35 g |
| 180 ct | 36 g |
| 200 ct | 40 g |
| 225 ct | 45 g |
| 250 ct | 50 g |
| 275 ct | 55 g |
| 300 ct | 60 g |
| 350 ct | 70 g |
| 400 ct | 80 g |
| 450 ct | 90 g |
| 500 ct | 100 g |
| 600 ct | 120 g |
| 750 ct | 150 g |
| 1000 ct | 200 g |
| 2000 ct | 400 g |
| 5000 ct | 1000 g |
Real-world reference
A typical engagement-ring diamond is around 1 carat. A large ruby might weigh 3–5 carats. In grams, that gives you: 1 ct = 0.2 g, 10 ct = 2 g, 100 ct = 20 g.
Frequently asked questions
- How many grams are in 1 carat?
- 1 carat equals 0.2 grams.
- How do I convert carats to grams?
- Multiply the carat value by 0.2. So x ct × 0.2 = the equivalent in g.
- What is 5 carats in grams?
- 5 carats equals 1 grams.
- What is 10 carats in grams?
- 10 carats equals 2 grams.
- What is 100 carats in grams?
- 100 carats equals 20 grams.
- How do I convert back from grams to carats?
- Multiply the gram value by 5. For example, 1 g = 5 ct.
- Is the carat bigger than the gram?
- No. 1 carat is smaller than 1 gram. It takes 5 carats to equal 1 gram.
- Are these conversion factors exact?
- The factor is derived directly from the SI definitions of carat and gram; the displayed value is rounded for readability, and the browser computes using IEEE 754 double-precision arithmetic.
About the carat and the gram
The gram
The gram (g) is a metric unit of mass equal to one-thousandth of a kilogram. It is the everyday unit for food labeling, postage, jewelry, and laboratory measurements. The 2019 SI redefinition fixed the kilogram (and therefore the gram) in terms of Planck's constant, ending more than a century of dependence on a physical prototype.