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Carats to Milligrams Converter

Enter the weight in carats below to convert it to milligrams.

Convert Carats to Milligrams

Enter a value in carats (ct) to convert to milligrams (mg).

Result
•
1,000milligrams
5 ct = 1,000 mg
Result updates automatically
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Equivalent Measurements Across UnitsFor 5 ct
Milligrams1,000 mg
Grams1 g
Kilograms0.001 kg
Ounces0.03527 oz
Pounds0.00220462 lb
Stones0.00015747 st
Suggested Conversions
Reference:NIST OWM (SI Units — Mass)
[1–3] ↓

Metric Carat to Milligram Conversion Table

Table showing various metric carat measurements converted to milligrams. Click any preset value or arrow to load it into the converter.

Carats (ct)Milligrams (mg)
1 ct200 mg
2 ct400 mg
2.5 ct500 mg
5 ct1,000 mg
10 ct2,000 mg
15 ct3,000 mg
20 ct4,000 mg
25 ct5,000 mg
30 ct6,000 mg
50 ct10,000 mg

How to Convert Carats to Milligrams

To convert carats to milligrams, multiply the weight by the following conversion ratio: 200 milligrams/metric carat.

Since one metric carat is equal to 200 milligrams, you can use this simple formula to convert:

milligrams = carats × 200

The weight in milligrams is equal to the weight in carats multiplied by 200.

For example, here's how to convert 5 carats to milligrams using the formula above.

milligrams = (5 ct × 200) = 1,000 mg

How Many Milligrams Are in a Metric Carat?

There are 200 milligrams in a metric carat, which is why we use this value in the formula above.

1 ct = 200 mg|1 mg = 0.005 ct

Our metric carat to milligram calculator automatically converts your weight measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.

Carats and milligrams are both units used to measure weight. Keep reading to learn more about each unit.

What Is a Metric Carat?

A metric carat is a unit of weight equal to 1/5,000 of a kilogram (0.0002 kg). Gemstone mass unit equal to 0.2 grams (200 mg). [1]

The metric carat is classified as a metric and SI-compatible unit of weight. Carats can be abbreviated as ct; for example, 1 metric carat can be written as 1 ct.

When working with carats (ct) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.

In practice, carats (ct) are widely used across fine-tolerance laboratory, analytical, and micro-scale weight measurements within SI metric workflows, engineering documentation, and technical data sheets.

What Is a Milligram?

A milligram is a unit of weight equal to 1/1,000,000 of a kilogram (0.000001 kg). One-thousandth of a gram (10⁻⁶ kg). [2]

The milligram is classified as a metric and SI-compatible unit of weight. Milligrams can be abbreviated as mg; for example, 1 milligram can be written as 1 mg.

In the metric system, "milli" is the standard SI prefix for thousandths, or 10⁻³. This makes the milligram (mg) a convenient decimal multiple of the gram (g).

In practice, milligrams (mg) are widely used across fine-tolerance laboratory, analytical, and micro-scale weight measurements within SI metric workflows, engineering documentation, and technical data sheets.

When converting weight between carats (ct) and milligrams (mg), keep full floating-point precision (1 ct = 200 mg; 1 mg = 0.005 ct) during intermediate calculations and round only the final milligram figure to match your instrument tolerance.

More Carat & Milligram Conversions

Need to calculate in the opposite direction? Use our milligrams to carats calculator to switch your starting unit immediately. You can also explore related tools such as converting milligrams to carats, converting micrograms to milligrams, or converting grams to milligrams.

Frequently Asked Questions

There are 200 milligrams (mg) in 1 metric carat (ct). Conversely, 1 milligram (mg) is equal to 0.005 carats (ct).

References

NIST · BIPM · ISO
  1. [1]
    NIST OWM (SI Units — Mass)·Mass & Weight Metrology Standard — Carats (ct) to Milligrams (mg)
    NIST OWM Standard
  2. [2]
    NIST HB 44 (NIST Handbook 44 (Current Ed.))·Unit Specifications: Metric Carat (ct) & Milligram (mg)
    NIST HB 44 Specification
  3. [3]
    BIPM (SI Base Unit: Kilogram (kg))·Conversion Factors & Mathematical Basis (ct to mg)
    BIPM Reference
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