Convert Carat to Microgram (ct → µg)
The carat equals 200 milligrams exactly and is the universal unit for gemstone and diamond weight in jewelry.
Carat to Microgram Conversion Table
10 common values| Carat | Microgram |
|---|---|
| 1 ct | 200,000 µg |
| 5 ct | 1,000,000 µg |
| 10 ct | 2,000,000 µg |
| 25 ct | 5,000,000 µg |
| 50 ct | 10,000,000 µg |
| 100 ct | 20,000,000 µg |
| 250 ct | 50,000,000 µg |
| 500 ct | 100,000,000 µg |
| 1,000 ct | 200,000,000 µg |
| 5,000 ct | 1,000,000,000 µg |
How to Convert Carat to Microgram Manually
Step by StepConverting carats to micrograms is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.
- 1Take your value in caratsStart with the number of carats (ct) you want to convert.
- 2Multiply by 200,000The conversion factor from ct to µg is 200,000. Multiply your value by this number.
- 3Read the result in microgramsThe result is your value in micrograms (µg).
Formula
Multiply the value in carats by 200,000. For the reverse direction, multiply by 0.000005.
µg = ct × 200,000ct = µg × 0.000005Tips
Use these in everyday conversions- 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".
Common Mistakes
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.
About Carat and Microgram
What is the Carat?
The carat equals exactly 200 milligrams (0.2 g) and is the universal unit for gemstone and diamond weight in the global jewelry industry. The word derives from the Greek 'keration' and the Arabic 'qīrāṭ,' both referring to carob seeds, which were once used as natural counterweights for weighing gems because they have remarkably uniform mass. The metric carat was standardized in 1907 at exactly 200 mg, replacing dozens of regional carat values that had varied between 188 and 213 mg. A 1-carat diamond is roughly 6.5 mm in diameter, and the famous Hope Diamond weighs 45.52 carats. The carat is distinct from the karat (with a 'k'), which measures gold purity (24-karat = 100% gold). It relates to the gram (5 ct = 1 g) and the milligram (200 mg = 1 ct). Gem dealers commonly use 'points' for fractions (100 points = 1 carat).
- Diamond and gemstone retail and valuation
- Jewellery manufacturing and design
- International gem certification (GIA, IGI)
A 1-carat diamond weighs 200 mg and is typically 6.5 mm across. The Hope Diamond is 45.52 carats (9.1 g).
What is the Microgram?
The microgram equals one millionth of a gram (10⁻⁶ g) and is the standard unit for very small mass measurements in pharmacology, environmental science, and trace-element nutrition. The Greek letter µ (mu) represents the SI prefix 'micro' (one millionth). Vitamin B12 daily intake is around 2.4 µg, and the lethal dose of botulinum toxin is in the nanogram-to-microgram range, making it one of the most potent biological substances known. The microgram is critical in air-quality monitoring (PM concentrations in µg/m³), trace-mineral supplements (selenium, iodine), and pharmaceutical compounding. It relates to the milligram (1,000 µg = 1 mg) and the nanogram (1,000 ng = 1 µg). Environmental regulators set legal limits on heavy metals (lead, arsenic) in drinking water in micrograms per liter.
- Vitamin D, A and K dosing
- Trace metal content in food and water
- Hormone replacement therapy dosing
Vitamin D adult dose: 15–20 µg/day. Selenium RDA: 55 µg/day. Many thyroid medications are dosed in µg.