Convert carats to milligrams

1 ct=200mg

Use the converter below to change any carats value into milligrams instantly — with formula, conversion table, and real-world examples.

You have

Equals

200

Conversion formula

Forward

milligrams = carats × 200

Reverse

carats = milligrams × 0.005

Example: 10 ct × 200 = 2,000 mg.

About both units

From

Carat

The metric carat equals 200 milligrams exactly. It is the standard unit for gemstone weight — diamonds, rubies, sapphires and emeralds are sold by the carat. Do not confuse with the purity carat (karat) used for gold (24K = pure gold).

Real-world: A 1-carat diamond weighs 200 mg and is typically 6.5 mm across. The Hope Diamond is 45.52 carats (9.1 g).

Read full carat reference →

Milligram

The milligram equals one thousandth of a gram. It is the dosing unit for most oral medications. A standard paracetamol tablet contains 500 mg. The daily recommended intake of iron for adult men is 8 mg, for women 18 mg. Micrograms (µg) are used for even smaller quantities like vitamin D.

Real-world: A paracetamol tablet is 500 mg. Daily iron intake: 8 mg (men) / 18 mg (women). Aspirin for heart protection: 75–100 mg daily.

Read full milligram reference →

Carat to Milligram conversion table

Common carats to milligrams values for quick reference.

Carat (ct)	Milligram (mg)
1 ct	200 mg
5 ct	1,000 mg
10 ct	2,000 mg
25 ct	5,000 mg
50 ct	10,000 mg
100 ct	20,000 mg
250 ct	50,000 mg
500 ct	100,000 mg
1,000 ct	200,000 mg
5,000 ct	1,000,000 mg

Tips & common mistakes

Quick tips

1 carat = 200 mg = 0.2 g exactly since 1907.
Carat (gem weight) and karat (gold purity, 24 K = pure) are different words with different meanings.
A carat is divided into 100 points; a 0.25 ct diamond is called a "25-pointer".

Avoid these

Confusing carat (mass) with karat (gold purity).
Assuming a 2-carat diamond is twice the physical size of a 1-carat — volume scales with cube root of mass.
Using "karat" on gemstone certificates — international standard is "carat" spelled with a C.

Frequently asked questions

How many milligrams in a carat?

One carat equals 200 milligrams.

How do I convert carats to milligrams?

Multiply the carat value by 200 to get the equivalent in milligrams.

What is 100 carats in milligrams?

100 carats equals 20,000 milligrams.

Is a carat bigger than a milligram?

Yes. 1 carat equals 200 milligrams, so one carat is larger.

How to convert carats to milligrams without a calculator?

Multiply by 200 for a quick estimate; use a calculator for precise results.

Related weight conversions

📊 See full comparison matrix →

Conversions in other categories

LengthKilometer → Mile TemperatureCelsius → Fahrenheit VolumeLiter → US Gallon AreaSquare Meter → Square Foot SpeedKilometer per Hour → Mile per Hour EnergyKilojoule → Kilocalorie PressureBar → Pound per Square Inch PowerKilowatt → Mechanical Horsepower