Carat (ct) Weight Conversion Calculator

Carat Conversion Calculator

Enter a value in carats below to convert to another unit of weight.

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What Is a Carat?

A carat is a unit used to measure weight.

A carat is sometimes also referred to as a metric carat. Carats can be abbreviated as ct, and are also sometimes abbreviated as CD. For example, 1 carat can be written as 1 ct or 1 CD.

Background and Origin

Historically, various regions and countries have had their own version of the carat for use in measuring gold. The carat was standardized as a unit of a measure in 1877 and originally was equal to 205 milligrams of mass. It was later redefined at a convention in 1907 as being equal to 200 milligrams.

Uses

The carat is widely used for measuring the weight of diamonds, gemstones, and pearls.

How Much Is a Carat?

The carat is a unit of mass/weight equal to 200 milligrams.^[1]

How to Convert Carats

To convert carats to another unit of weight, you need to multiply the value by a conversion factor. A conversion factor is a numerical value used to change the units of a measurement without changing the value.^[2]

You can find the conversion factors for carats in the conversion table below.

Then, multiply the weight measurement by the conversion factor to find the equivalent value in the desired unit of measurement.

carats × conversion factor = result

You can also use a calculator, such as one of the converters below, for the conversion.

Carat Conversion Table

Common carat values and equivalent imperial and metric weight measurements
carats	tons	pounds	ounces	metric tons	kilograms	grams	milligrams	long tons
1 ct	0.00000022046 t	0.000441 lb	0.007055 oz	0.0000002 t	0.0002 kg	0.2 g	200 mg	0.00000019684 lt
2 ct	0.00000044092 t	0.000882 lb	0.01411 oz	0.0000004 t	0.0004 kg	0.4 g	400 mg	0.00000039368 lt
3 ct	0.00000066139 t	0.001323 lb	0.021164 oz	0.0000006 t	0.0006 kg	0.6 g	600 mg	0.00000059052 lt
4 ct	0.00000088185 t	0.001764 lb	0.028219 oz	0.0000008 t	0.0008 kg	0.8 g	800 mg	0.00000078737 lt
5 ct	0.0000011023 t	0.002205 lb	0.035274 oz	0.000001 t	0.001 kg	1 g	1,000 mg	0.00000098421 lt
6 ct	0.0000013228 t	0.002646 lb	0.042329 oz	0.0000012 t	0.0012 kg	1.2 g	1,200 mg	0.000001181 lt
7 ct	0.0000015432 t	0.003086 lb	0.049384 oz	0.0000014 t	0.0014 kg	1.4 g	1,400 mg	0.0000013779 lt
8 ct	0.0000017637 t	0.003527 lb	0.056438 oz	0.0000016 t	0.0016 kg	1.6 g	1,600 mg	0.0000015747 lt
9 ct	0.0000019842 t	0.003968 lb	0.063493 oz	0.0000018 t	0.0018 kg	1.8 g	1,800 mg	0.0000017716 lt
10 ct	0.0000022046 t	0.004409 lb	0.070548 oz	0.000002 t	0.002 kg	2 g	2,000 mg	0.0000019684 lt
11 ct	0.0000024251 t	0.00485 lb	0.077603 oz	0.0000022 t	0.0022 kg	2.2 g	2,200 mg	0.0000021653 lt
12 ct	0.0000026455 t	0.005291 lb	0.084658 oz	0.0000024 t	0.0024 kg	2.4 g	2,400 mg	0.0000023621 lt
13 ct	0.000002866 t	0.005732 lb	0.091712 oz	0.0000026 t	0.0026 kg	2.6 g	2,600 mg	0.0000025589 lt
14 ct	0.0000030865 t	0.006173 lb	0.098767 oz	0.0000028 t	0.0028 kg	2.8 g	2,800 mg	0.0000027558 lt
15 ct	0.0000033069 t	0.006614 lb	0.105822 oz	0.000003 t	0.003 kg	3 g	3,000 mg	0.0000029526 lt
16 ct	0.0000035274 t	0.007055 lb	0.112877 oz	0.0000032 t	0.0032 kg	3.2 g	3,200 mg	0.0000031495 lt
17 ct	0.0000037479 t	0.007496 lb	0.119931 oz	0.0000034 t	0.0034 kg	3.4 g	3,400 mg	0.0000033463 lt
18 ct	0.0000039683 t	0.007937 lb	0.126986 oz	0.0000036 t	0.0036 kg	3.6 g	3,600 mg	0.0000035431 lt
19 ct	0.0000041888 t	0.008378 lb	0.134041 oz	0.0000038 t	0.0038 kg	3.8 g	3,800 mg	0.00000374 lt
20 ct	0.0000044092 t	0.008818 lb	0.141096 oz	0.000004 t	0.004 kg	4 g	4,000 mg	0.0000039368 lt

Carat Conversion Calculators

You can also convert weight using one of our carat converters below.

US Customary & Imperial Units

SI Units

Other Units

References

National Institute of Standards and Technology, Precious Metals Conversion Information, https://www.nist.gov/pml/owm/laws-and-regulations/precious-metals-conversion
National Institute of Standards & Technology, Unit Conversion, https://www.nist.gov/pml/owm/metric-si/unit-conversion