How many carats are in 1 gram?

One gram equals exactly 5 carats. This is an exact conversion because the metric carat was defined as exactly 200 milligrams (0.2 grams) in 1907.

How do I convert grams to carats?

Multiply the number of grams by 5. For example, 0.8 grams × 5 = 4 carats. This is one of the simplest unit conversions in metrology.

How heavy is a 1-carat diamond?

A 1-carat diamond weighs exactly 0.2 grams (200 milligrams). A round brilliant diamond of 1 carat has a diameter of approximately 6.5 mm.

Grams to Carats (g to ct) Converter

1 g = 5 ct

1 Gram equals 5 Carats (1 g = 5 ct). Convert Grams to Carats with formula, table, and examples.

One gram equals exactly 5 carats. This conversion is used by gemologists, jewelers, and gem traders who need to express a gemstone's weight in the industry-standard carat unit when the stone has been weighed on a gram scale.

How to Convert Grams to Carats

ct = g × 5

Multiply the value in Grams by 5

Take your value in Grams
Multiply by 5
Read the result in Carats

Common Grams to Carats Conversions

Grams (g)	Carats (ct)	Status
1 g	5 ct
2 g	10 ct
5 g	25 ct
10 g	50 ct
25 g	125 ct
50 g	250 ct
100 g	500 ct
500 g	2,500 ct
1,000 g	5,000 ct

Good to Know About Grams to Carats Conversion

The clean 5:1 ratio (5 carats per gram) makes this one of the easiest gemological conversions. Gem dealers memorize it instantly, unlike the awkward troy ounce conversion (31.1 grams) used for precious metals.

Grams to Carats: What You Need to Know

A gemstone weighing 0.5 grams is 2.5 carats. A parcel of loose diamonds weighing 10 grams contains 50 carats total. When buying rough gemstones by weight in grams, converting to carats helps estimate the yield of cut stones and their per-carat value.

What is a Gram? g

A metric unit of mass equal to one thousandth of a kilogram. Widely used in cooking, nutrition labeling, and science.

Metric cooking nutrition labels postal weight

Learn more about Gram →

What is a Carat? ct

A carat is a unit of mass equal to exactly 200 milligrams (0.2 grams), used for measuring gemstones and pearls. Adopted internationally in 1907 by the Fourth General Conference on Weights and Measures.

Metric diamond weight gemstone grading pearl measurement

Learn more about Carat →

Going the other way? Use our Carats to Grams converter.

Grams to Carats FAQ

One gram equals exactly 5 carats. This is an exact conversion because the metric carat was defined as exactly 200 milligrams (0.2 grams) in 1907.
Multiply the number of grams by 5. For example, 0.8 grams × 5 = 4 carats. This is one of the simplest unit conversions in metrology.
A 1-carat diamond weighs exactly 0.2 grams (200 milligrams). A round brilliant diamond of 1 carat has a diameter of approximately 6.5 mm.

Non-Frequently Asked Questions About Grams to Carats

Questions nobody should ask - but someone did.

No. A gram is 1/1000 of a kilogram. A grandma is priceless. Though both may appear in the kitchen - one on the scale, the other making sure you eat enough.