How many grams are in 1 carat?

1 carat equals 0.2 grams exactly. This is the standard metric carat used globally for gemstones.

How do I convert carats to grams?

Use the formula: grams = carats × 0.2. Example: 2.5 carats × 0.2 = 0.5 grams.

How do I convert grams to carats?

Use the formula: carats = grams × 5. Example: 1 gram × 5 = 5 carats.

Is carat the same as karat?

No. Carat (ct) measures gemstone weight; karat (K) measures gold purity.

Why use milligrams in gem measurements?

Gemstone grading often needs fine precision. Since 1 carat = 200 mg, milligrams help with detailed valuation and lab reporting.

Is this conversion exact?

Yes. The metric carat is defined exactly as 200 milligrams (0.2 grams).

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Gem Weight Converter

Carats to Grams Converter

Convert carats (ct) to grams (g) and grams to carats instantly. Perfect for diamond and gemstone measurements, jewelry listings, and precision weight references.

Last updated: April 8, 2026

Bidirectional carats ↔ grams

Exact metric carat standard

Includes milligram precision

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Carats to Grams Converter

Convert carats (ct) to grams (g) and grams to carats instantly. Useful for jewelry, gemstones, and precision trade weights.

Carats (ct)

Grams (g)

Conversion Results

Carats

1 ct

Grams

0.2 g

Milligrams

200 mg

Quick facts

1 carat = 0.2 grams (exact)
1 gram = 5 carats (exact)
1 carat = 200 milligrams

Carats to Grams Converter Features

Exact formula

Carats to grams

Formula

g = ct × 0.2

Reverse formula

Grams to carats

Formula

ct = g × 5

Precision support

Jewelry workflows

Also shown

milligrams (mg)

Quick Example Result

Converting 1 carat:

Input

1 ct

Result

0.2 g

How Our Carats to Grams Converter Works

The metric carat is internationally standardized at exactly 200 milligrams. That gives the exact conversion relationship of 1 ct = 0.2 g and 1 g = 5 ct. This converter applies those definitions directly.