How many grams is 1 carat?

Exactly 0.2 grams. The metric carat has been defined as 200 milligrams (0.2 g) since 1907 and is the universal standard for gemstone weighing.

Is this the same carat as used for gold purity?

No. The carat used here is the metric carat (ct), a unit of mass equal to 0.2 g. Gold purity uses karat (k or kt), which measures fineness out of 24 parts — a completely different concept.

How many carats is 1 gram?

Exactly 5 carats. Because 1 ct = 0.2 g, inverting gives 1 g = 5 ct. The reverse converter on this page calculates this automatically.

Why is the carat exactly 0.2 grams?

The value was standardized internationally in 1907 to replace inconsistent regional carat weights. Defining it as 200 mg (0.2 g) aligned it cleanly with the metric system.

Can I convert fractional carats?

Yes. This tool accepts any positive decimal value, including common gemstone weights like 0.25 ct, 0.5 ct, 1.0 ct, or 1.5 ct. Results are shown to six decimal places for precision.

Carats to Grams Converter

Name: Carats to Grams Converter
Availability: InStock
Author: Nham Vu

Enter a weight in carats and instantly get the equivalent in grams (1 ct = 0.2 g exactly).

Convert Carats to Grams

Carats (ct)

Grams (g)

Reverse: Grams to Carats

Grams (g)

Carats (ct)

Quick Reference Table

1 carat (ct) = 0.2 grams (g) exactly

Carats (ct)	Grams (g)

Formula

grams = carats × 0.2

carats = grams ÷ 0.2

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Summary

Enter a weight in carats and instantly get the equivalent in grams (1 ct = 0.2 g exactly).

How it works

Enter a weight in carats in the top input field.
The converter multiplies your value by 0.2 to get grams.
The gram result appears instantly — no button press needed.
Use the reverse field to convert grams back to carats.
Click "Copy Result" to copy the converted value to your clipboard.

Use cases

Look up the gram weight of a diamond or gemstone listed in carats.
Compare gemstone weights when shopping across different marketplaces.
Convert lab report carat weights into metric grams for invoicing.
Calculate precious metal mass for jewelry design and manufacturing.
Verify carat-to-gram conversions on certificates and appraisal reports.
Teach students the carat unit and its relation to the metric system.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu