Carats to Milligrams
Convert any value from carat to milligram with full precision. Use the converter above for instant results, or read on for the exact formula, worked examples, common uses, and answers to frequently asked questions.
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About the Carat to Milligram conversion
Mass and weight conversions come up everywhere — in cooking, shipping, science, fitness, and international trade. Although mass and weight are technically different (mass is the amount of matter, weight is the force gravity exerts on that matter), the everyday conversions between pounds, kilograms, ounces, grams, and stones are what most people need.
This page focuses specifically on converting carat to milligram. Use the converter above for instant results, or read on for what each unit is, the exact formula, a worked example, and answers to common questions.
Understanding carat and milligram
What is a carat?
The metric carat is exactly 200 milligrams, or 0.2 gram. It is the standard unit for the mass of gemstones and pearls.
What is a milligram?
The milligram is one thousandth of a gram, or one millionth of a kilogram. It is standard for medicine doses, vitamins, and other small quantities.
How a carat compares to a milligram
The carat is the larger of the two units: one carat is about 200 milligram. Because the milligram is smaller, the same length or quantity works out to a larger number when you measure it with that unit. Knowing which unit is larger is a quick way to sanity-check a conversion: if the numbers move in the wrong direction, the two units have probably been swapped.
Conversion formula
The exact mathematical relationship between carat and milligram is:
1 carat = 200 milligram
So to convert a value V from carat to milligram, use:
Vmilligram = Vcarat × 200
To go in the opposite direction:
Vcarat = Vmilligram × 0.005
These factors come from the international definitions published by NIST, BIPM, and ISO 80000 and are exact within their respective standard systems. The converter applies them with full floating-point precision.
Worked example
Using the formula above, here are some common values converted from Carat to Milligram:
| Carat | Milligram |
|---|---|
| 1 | 200 |
| 5 | 1000 |
| 10 | 2000 |
| 25 | 5000 |
| 50 | 10000 |
| 100 | 20000 |
Sources and accuracy
The kilogram was redefined in 2019 by fixing the Planck constant (NIST, BIPM). All metric mass units derive from this base. The international avoirdupois pound (0.45359237 kg) was agreed in the 1959 international yard and pound agreement between English-speaking nations. Troy weights (used for precious metals) follow the troy system standardized in 1828 by the U.S. Mint.
Conversion factors are cross-checked against the NIST SP 811 guide, the BIPM SI brochure, and ISO 80000, plus published historical references for older unit systems. For mission-critical work such as medical dosing, legal-for-trade measurement, aerospace, or large-scale engineering, always verify independently with the original source.
Practical tips
A common source of error is mixing troy and avoirdupois ounces: one troy ounce is about 31.1 g while one avoirdupois ounce is about 28.35 g. Use the troy ounce option only when measuring gold, silver, platinum, or gemstones.
Frequently asked questions
How many milligram are in one carat?
One carat equals 200 milligram. To convert, multiply your carat value by 200.
Which is bigger, a carat or a milligram?
The carat is bigger. One carat equals about 200 milligram.
How accurate is this carat to milligram converter?
It uses the official international conversion factors from NIST and BIPM with full double-precision floating-point accuracy. For everyday use the result is precise to many more decimal places than any practical measurement requires.
Can I convert milligram back to carat as well?
Yes. Use the swap button above to reverse the From and To fields, or change either dropdown to any unit in the weight & mass category. The calculation runs entirely in your browser, so it also works offline once the page has loaded.