# Carats to Milligrams (ct to mg) Source: https://www.unitconvertercalculator.com/weight/carats-to-milligrams/ **1 ct = 200 mg** One carat equals exactly 200 milligrams. This is the defining relationship of the modern metric carat, established by international agreement in 1907. The milligram conversion is the most fundamental one for the carat, since the carat was literally defined as 200 milligrams. No rounding, no approximation - a clean, exact 200. ## Formula Apply the conversion factor ## Conversion Table | Carats (ct) | Milligrams (mg) | |---|---| | 0.01 ct | 2 mg | | 0.05 ct | 10 mg | | 0.1 ct | 20 mg | | 0.25 ct | 50 mg | | 0.5 ct | 100 mg | | 0.75 ct | 150 mg | | 1 ct | 200 mg | | 1.5 ct | 300 mg | | 2 ct | 400 mg | | 3 ct | 600 mg | | 5 ct | 1000 mg | | 10 ct | 2000 mg | | 25 ct | 5000 mg | | 50 ct | 10000 mg | | 100 ct | 20000 mg | | 500 ct | 100000 mg | ## Units ### 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. ### Milligram (mg) A metric unit of mass equal to one thousandth of a gram, or one millionth of a kilogram. Commonly used in medicine and pharmacology. ## Background Jewelers use milligrams when carat notation is insufficient for very small stones. A 10-point diamond (0.1 carat) weighs exactly 20 milligrams. Pharmaceutical scales that measure in milligrams can double as gem-weighing instruments for small accent stones and melee diamonds. Gemological laboratories like the GIA report weights to the nearest milligram when grading stones below 0.5 carats. ## Good to Know Before the 1907 standardization, the carat varied by country and sometimes by city. The Florentine carat was about 197 mg, the London carat 205 mg, and the South African carat 206 mg. International gemstone trade was plagued by these discrepancies. The adoption of a universal 200 mg carat was one of the earliest successful acts of global measurement standardization, predating many other international standards. ## FAQ ### How many milligrams are in one carat? One carat equals exactly 200 milligrams. This is not an approximation - the metric carat is defined as 200 mg. ### How is the carat subdivided? The carat is divided into 100 'points.' One point equals 2 milligrams. A '50-point diamond' is 0.5 carats (100 mg), and a '25-point diamond' is 0.25 carats (50 mg). This point system allows jewelers to avoid decimal notation. ### Is a carat the same as a karat? No. A carat (ct) measures gemstone weight (200 mg). A karat (kt or K) measures gold purity - 24 karat means pure gold, 18 karat means 75% gold. They share an etymological root (carob seeds) but are completely different measurements. ## Non-Frequently Asked Questions ### Does a 200 mg ibuprofen tablet weigh the same as a 1-carat diamond? Exactly the same. A standard 200 mg ibuprofen tablet and a 1-carat diamond are identical in weight. The difference in value is somewhat significant: the tablet costs a few cents, while the diamond costs several thousand dollars. Swallowing the wrong one would be regrettable. ### How many carats is a mosquito? An average mosquito weighs about 2.5 milligrams, which is 0.0125 carats - roughly one-eightieth of a carat. So a swarm of 80 mosquitoes weighs as much as a 1-carat diamond. The mosquitoes are considerably less desirable at a dinner party. ### If I licked my finger and picked up a grain of sugar, how many carats did I just eat? A single grain of granulated sugar weighs about 625 micrograms or 0.625 milligrams, which is 0.003125 carats. You would need to lick about 320 individual sugar grains to consume one carat's worth. 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