Convert Carat to Milligram
1 carat = 200 milligram (mg). For example, 10 carat = 2,000 milligram and 100 carat = 20,000 milligram. Type any value below to convert carat to milligram both ways — it runs entirely in your browser.
Quick answer: Carat to Milligram
1 Carat = 200 Milligram (ct → mg). To convert carat to milligram, multiply by 200. To convert milligram to carat, multiply by 0.005. The converter at the top does this instantly and both ways; the sections below give the formula, worked examples, a full conversion chart and answers to the most common carat-to-milligram questions.
How to convert Carat to Milligram
To convert carat to milligram, multiply the number of carat by the conversion factor 200, because 1 ct = 200 mg. The conversion is linear, so the same factor works for any value — whole numbers, decimals or fractions. For the reverse direction, 1 mg = 0.005 ct, so you divide by 200 (or multiply by 0.005) to turn milligram back into carat.
mg = ct × 200 ·
ct = mg × 0.005
- Write down the value you want to convert, in carat.
- Multiply it by 200.
- The result is the same area/length/quantity expressed in milligram.
Carat to Milligram — worked examples
Each row shows the exact arithmetic so you can follow the conversion step by step. For example, 5 carat is 1,000 milligram because 5 ct × 200 = 1,000 mg.
| Carat | Calculation | Milligram |
|---|---|---|
| 1 ct | 1 ct × 200 = 200 mg | 200 mg |
| 2 ct | 2 ct × 200 = 400 mg | 400 mg |
| 3 ct | 3 ct × 200 = 600 mg | 600 mg |
| 5 ct | 5 ct × 200 = 1,000 mg | 1,000 mg |
| 7 ct | 7 ct × 200 = 1,400 mg | 1,400 mg |
| 10 ct | 10 ct × 200 = 2,000 mg | 2,000 mg |
| 12 ct | 12 ct × 200 = 2,400 mg | 2,400 mg |
| 15 ct | 15 ct × 200 = 3,000 mg | 3,000 mg |
| 20 ct | 20 ct × 200 = 4,000 mg | 4,000 mg |
| 25 ct | 25 ct × 200 = 5,000 mg | 5,000 mg |
| 50 ct | 50 ct × 200 = 10,000 mg | 10,000 mg |
| 100 ct | 100 ct × 200 = 20,000 mg | 20,000 mg |
Common Carat to Milligram conversions
These are the carat-to-milligram values people look up most often. Every figure is computed from the exact factor, so you can rely on them for quick reference:
- 1 carat = 200 milligram
- 2 carat = 400 milligram
- 2.5 carat = 500 milligram
- 3 carat = 600 milligram
- 4 carat = 800 milligram
- 5 carat = 1,000 milligram
- 6 carat = 1,200 milligram
- 7 carat = 1,400 milligram
- 8 carat = 1,600 milligram
- 9 carat = 1,800 milligram
- 10 carat = 2,000 milligram
- 12 carat = 2,400 milligram
- 15 carat = 3,000 milligram
- 20 carat = 4,000 milligram
- 25 carat = 5,000 milligram
- 30 carat = 6,000 milligram
- 50 carat = 10,000 milligram
- 75 carat = 15,000 milligram
- 100 carat = 20,000 milligram
- 200 carat = 40,000 milligram
- 500 carat = 100,000 milligram
- 1000 carat = 200,000 milligram
Carat to Milligram conversion chart (both directions)
The chart below converts carat to milligram and milligram to carat side by side, so it works whichever way you need. 1 carat = 200 milligram, and 1 milligram = 0.005 carat.
| Carat → Milligram | Milligram → Carat |
|---|---|
| 0.25 ct = 50 mg | 0.25 mg = 0.00125 ct |
| 0.5 ct = 100 mg | 0.5 mg = 0.0025 ct |
| 1 ct = 200 mg | 1 mg = 0.005 ct |
| 2 ct = 400 mg | 2 mg = 0.01 ct |
| 3 ct = 600 mg | 3 mg = 0.015 ct |
| 4 ct = 800 mg | 4 mg = 0.02 ct |
| 5 ct = 1,000 mg | 5 mg = 0.025 ct |
| 6 ct = 1,200 mg | 6 mg = 0.03 ct |
| 7 ct = 1,400 mg | 7 mg = 0.035 ct |
| 8 ct = 1,600 mg | 8 mg = 0.04 ct |
| 9 ct = 1,800 mg | 9 mg = 0.045 ct |
| 10 ct = 2,000 mg | 10 mg = 0.05 ct |
| 12 ct = 2,400 mg | 12 mg = 0.06 ct |
| 15 ct = 3,000 mg | 15 mg = 0.075 ct |
| 20 ct = 4,000 mg | 20 mg = 0.1 ct |
| 25 ct = 5,000 mg | 25 mg = 0.125 ct |
| 30 ct = 6,000 mg | 30 mg = 0.15 ct |
| 40 ct = 8,000 mg | 40 mg = 0.2 ct |
| 50 ct = 10,000 mg | 50 mg = 0.25 ct |
| 75 ct = 15,000 mg | 75 mg = 0.375 ct |
| 100 ct = 20,000 mg | 100 mg = 0.5 ct |
| 150 ct = 30,000 mg | 150 mg = 0.75 ct |
| 200 ct = 40,000 mg | 200 mg = 1 ct |
| 250 ct = 50,000 mg | 250 mg = 1.25 ct |
| 500 ct = 100,000 mg | 500 mg = 2.5 ct |
| 1000 ct = 200,000 mg | 1000 mg = 5 ct |
Carat vs Milligram: which is bigger?
A carat is the larger unit: one carat equals 200 milligrams. Put another way, you need 200 milligrams to make a single carat.
What is a Carat? History, origin and usage
The carat takes its name from the carob seed — keration in Greek — which gem traders used as a counterweight because the seeds were believed to be unusually uniform. They were not, in fact, especially uniform, and the carat varied from city to city until the 4th General Conference on Weights and Measures adopted the metric carat of exactly 200 milligrams in 1907.
The carat is the weight unit of the gemstone trade. Diamond, ruby, sapphire and emerald weights are quoted in carats, and because price rises steeply with size, a stone of twice the carat weight can cost far more than twice as much.
Carat weight and karat purity are different things that sound identical: a 2-carat diamond is a statement about mass, while 22-karat gold is a statement about how much of an alloy is gold, out of 24 parts. Jewellers also split the carat into 100 "points", so a 0.25-carat stone is called a 25-pointer.
What is a Milligram? History, origin and usage
The milligram arrived with the metric system itself in the 1790s as simply one thousandth of a gram — no separate standard was ever needed, because the metric prefixes do the work. It became important later, when chemistry and pharmacy started needing to state quantities far too small to write in grams.
Milligrams are the language of medicine and nutrition: tablet strengths, vitamin content, caffeine in a cup of coffee, and the daily limits on sodium or cholesterol are all written in milligrams.
A standard aspirin tablet is 325 milligrams and a grain of table salt is around 0.06 milligrams. Because doses are written this way, a single misplaced decimal point in a milligram figure is one of the classic causes of medication error.
Convert 1 Carat to other units
It can help to see a carat next to the other units it is commonly compared with. One carat (ct) is equal to:
| 1 Carat equals | Unit |
|---|---|
| 0.0002 kg | Kilogram |
| 0.2 g | Gram |
| 200 mg | Milligram |
| 200,000 µg | Microgram |
| 0.0000002 t | Tonne |
| 0.000002 q | Quintal |
| 0.0004409245 lb | Pound |
| 0.007054792 oz | Ounce |
| 0.00003149461 st | Stone |
| 0.0000002204623 ton (US) | Short ton |
| 0.0000001968413 ton (UK) | Long ton |
| 0.006430149 oz t | Troy ounce |
| 3.086472 gr | Grain |
Convert 1 Milligram to other units
One milligram (mg) is equal to:
| 1 Milligram equals | Unit |
|---|---|
| 0.000001 kg | Kilogram |
| 0.001 g | Gram |
| 1,000 µg | Microgram |
| 0.000000001 t | Tonne |
| 0.00000001 q | Quintal |
| 0.000002204623 lb | Pound |
| 0.00003527396 oz | Ounce |
| 0.000000157473 st | Stone |
| 0.000000001102311 ton (US) | Short ton |
| 0.0000000009842065 ton (UK) | Long ton |
| 0.00003215075 oz t | Troy ounce |
| 0.01543236 gr | Grain |
| 0.005 ct | Carat |
Tips for converting Carat to Milligram
- To go from carat to milligram, multiply by 200; to go back, divide by 200 (or multiply by 0.005).
- For a quick mental estimate, remember that 1 carat ≈ 200 milligram, so 10 carat ≈ 2,000 milligram.
- The converter above keeps full precision; the tables round for readability, so use the tool for exact figures.
- Both fields update live as you type — change either side to convert in that direction.
How to use this Carat to Milligram converter
Type a number into the Carat field and the equivalent in Milligram appears instantly — there is no “convert” button to press and nothing is sent to a server, so it works offline once the page has loaded and is safe for any data. You can also type into the Milligram field to convert the other way (milligram to carat). Use the swap control to flip the two units, and copy the result with a single click. Because the calculation runs in your browser with full floating-point precision, the converter is more exact than the rounded figures shown in the reference chart above — use the chart for quick look-ups and the tool for precise work.
Accuracy and method
Every figure on this page — the formula, the worked examples, the conversion chart and the “convert to other units” tables — is computed from a single verified conversion factor (1 ct = 200 mg), never copied from a hand-typed lookup table that could drift. That factor is derived from each unit’s definition in terms of a common base unit, and an automated check re-verifies all of the site’s factors on every update, so the numbers here stay correct over time. This matters for carat-to-milligram conversions because a small rounding error in a published table compounds quickly at larger quantities; computing from the exact factor avoids that.
Sources
- BIPM — The International System of Units (SI Brochure) — the defining document for the SI, published by the International Bureau of Weights and Measures. It fixes the base unit that this conversion resolves to, which is why the factor here can be exact rather than approximate.
- NIST — Definitions of the SI base units — the US National Institute of Standards and Technology reference for the SI base units, used here as an independent cross-check on the base-unit definition.
Weight factors here are exact, anchored to the kilogram: the international pound is exactly 0.45359237 kg, a stone is 14 pounds, a short ton is 2,000 pounds and a long ton is 2,240, a grain is 1/7000 of a pound and a metric carat is exactly 200 mg. So the live tool and every number on this page always agree.
Frequently asked questions
- How many milligram are in 1 carat?
- 1 carat = 200 milligram (mg). To convert any number of carat to milligram, multiply by 200.
- How do I convert carat to milligram?
- Multiply the number of carat by 200. For example, 10 carat = 10 × 200 = 2,000 milligram, and 25 carat = 5,000 milligram.
- How many carat are in 1 milligram?
- 1 milligram = 0.005 carat. So to convert milligram back to carat, multiply by 0.005.
- What is the formula to convert carat to milligram?
- milligram = carat × 200. The reverse formula is carat = milligram × 0.005.
- How much is 100 carat in milligram?
- 100 carat = 20,000 milligram. (And 1000 carat = 200,000 milligram.)
- Which is bigger, a carat or a milligram?
- A carat is larger: 1 carat = 200 milligram.
- Is this carat to milligram converter accurate?
- Yes — every value is computed from the exact 200 mg per ct factor (not rounded look-up tables), and the factors are re-verified automatically on every update.
- Can I convert milligram to carat too?
- Yes. The converter works both ways — enter a value in either field. 1 milligram = 0.005 carat.