How many kilograms is 1 carat?

1 metric carat equals exactly 0.0002 kilograms (200 milligrams). This is an internationally standardized definition adopted in 1907.

How many carats are in 1 kilogram?

There are exactly 5,000 metric carats in 1 kilogram, since 1 carat = 0.0002 kg and 1 / 0.0002 = 5,000.

Is the metric carat the same as a troy carat?

The modern metric carat (200 mg) replaced older regional carat standards. The troy system uses troy ounces and troy pounds, not carats, so they are different unit systems.

Why is the carat used for gemstones?

The carat originated from carob seeds historically used as counterweights for gemstone scales. The modern metric carat was standardized at 200 mg in the early 20th century for consistency worldwide.

How precise is this converter?

The conversion is mathematically exact: 1 carat = 0.0002 kg with no rounding error. The display rounds results to up to 10 significant decimal places to avoid floating-point noise.

Carats to Kilograms Converter

Enter a weight in carats and instantly get the equivalent in kilograms (1 ct = 0.0002 kg).

Weight in Carats

Enter carats (ct)

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Converted Weight

Enter carats on the left to see results

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Summary

The carats to kilograms converter uses the internationally defined metric conversion: 1 metric carat (ct) equals exactly 0.0002 kilograms, or 200 milligrams. This tool lets you enter any carat value and instantly see the equivalent weight in kilograms, grams, and milligrams for full context. It is useful for gemologists, jewelers, customs declarations, and scientific applications where precise stone weight must be expressed in SI units.

How it works

Enter the weight in carats in the input field.
The tool multiplies your value by 0.0002 to get kilograms.
Results are displayed in kilograms, grams, and milligrams simultaneously.
Use the Copy button to copy any result to your clipboard.
Clear the input to reset all fields.

Use cases

Converting diamond or gemstone weights for customs and import declarations.
Expressing gemstone carat weight in SI units for scientific or laboratory records.
Jewelry appraisers converting total stone weight to kilograms for shipping labels.
Students and educators verifying unit conversion in chemistry or physics.
Gemologists preparing certificates that require metric weight values.
Traders comparing gemstone lots quoted in carats with bulk weights in kilograms.

Frequently Asked Questions

Last updated: 2026-06-04 · Reviewed by Nham Vu