Grams to Carats
Type a value in either box to convert between grams and carats. The factor is 5.
| Grams | Carats |
|---|---|
| 1 g | 5 ct |
| 2 g | 10 ct |
| 3 g | 15 ct |
| 5 g | 25 ct |
| 10 g | 50 ct |
| 25 g | 125 ct |
| 50 g | 250 ct |
| 100 g | 500 ct |
How to use
- Enter a value in the Grams field.
- The Carats figure appears immediately — no button to press.
- Typing in the Carats field converts back to Grams the same way.
- Use the reference table for the values that come up most often.
Grams to Carats formula
To convert grams to carats, multiply by 5.
ct = g × 5
Put another way, one gram is exactly 5 carats.
Why this factor: the gram and the carat are both defined against the kilogram, so dividing one definition by the other gives 5 directly. Both definitions are set out in full below.
To go the other way, divide by 5 — or use the Carats to Grams converter, which is the same calculation reversed.
Worked example
Given 150 g, multiplying by 5 yields 750 ct.
150 g × 5 = 750 ct
The converter above does this for any value you type, in either direction.
What is a gram?
A gram is one thousandth of a kilogram, the everyday unit for food and small-object mass.
Definition: Exactly 0.001 kilogram by SI prefix definition.
Where it is used: Nutrition labels, recipes, postal rates, and laboratory weighing.
What is a carat?
A metric carat is the standard mass unit for gemstones.
Definition: Exactly 200 milligrams — that is, 0.2 gram — standardized internationally in 1907.
Where it is used: Diamond and gemstone weight throughout the jewellery trade.
Worth knowing: Do not confuse the carat (gemstone mass) with the karat (gold purity out of 24). A 1-carat diamond and 24-karat gold measure entirely different things.
Grams vs Carats
The gram is a metric unit while the carat is a specialized unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many carats are in a gram?
One gram equals 5 carats.
What is the formula to convert grams to carats?
Multiply the number of grams by 5. To reverse it, divide by 5 instead.
How do I convert carats back to grams?
Divide by 5, which is the same as multiplying by 0.2.
How many carats are in 10 grams?
10 g works out to 50 ct.
Is there anything to watch out for with carats?
Do not confuse the carat (gemstone mass) with the karat (gold purity out of 24). A 1-carat diamond and 24-karat gold measure entirely different things.
How is the gram defined?
Exactly 0.001 kilogram by SI prefix definition.