Carats to Kilograms
Convert carats to kilograms instantly — one carat is 0.0002 kilograms.
| Carats | Kilograms |
|---|---|
| 1 ct | 0.0002 kg |
| 2 ct | 0.0004 kg |
| 3 ct | 0.0006 kg |
| 5 ct | 0.001 kg |
| 10 ct | 0.002 kg |
| 25 ct | 0.005 kg |
| 50 ct | 0.01 kg |
| 100 ct | 0.02 kg |
How to use
- Enter a value in the Carats field.
- The Kilograms figure appears immediately — no button to press.
- Typing in the Kilograms field converts back to Carats the same way.
- Use the reference table for the values that come up most often.
Carats to Kilograms formula
The factor from carats to kilograms is 0.0002.
kg = ct × 0.0002
Put another way, one carat is exactly 1/5,000 of a kilogram.
Why this factor: the carat and the kilogram are both defined against the kilogram, so dividing one definition by the other gives 0.0002 directly. Both definitions are set out in full below.
To go the other way, divide by 0.0002 — or use the Kilograms to Carats converter, which is the same calculation reversed.
Worked example
Given 150 ct, multiplying by 0.0002 yields 0.03 kg.
150 ct × 0.0002 = 0.03 kg
The converter above does this for any value you type, in either direction.
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.
What is a kilogram?
The kilogram is the SI base unit of mass — the reference for every other mass unit.
Definition: Since 2019 the kilogram has been defined by fixing the Planck constant at exactly 6.62607015×10⁻³⁴ joule-seconds, retiring the physical platinum-iridium cylinder that defined it for 130 years.
Where it is used: Universal in science, trade and everyday weighing outside the United States.
Carats vs Kilograms
The carat is a specialized unit while the kilogram is an SI 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 kilograms are in a carat?
One carat equals 0.0002 kilograms.
What is the formula to convert carats to kilograms?
Multiply the number of carats by 0.0002. To reverse it, divide by 0.0002 instead.
How do I convert kilograms back to carats?
Divide by 0.0002, which is the same as multiplying by 5000.
How many kilograms are in 10 carats?
10 ct works out to 0.002 kg.
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 carat defined?
Exactly 200 milligrams — that is, 0.2 gram — standardized internationally in 1907.