Convert Microgram to Carat (µg → ct)

Converting micrograms to carats is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in micrograms

   Start with the number of micrograms (µg) you want to convert.
2. 2
   Multiply by 0.000005

   The conversion factor from µg to ct is 0.000005. Multiply your value by this number.
3. 3
   Read the result in carats

   The result is your value in carats (ct).

Multiply the value in micrograms by 0.000005. For the reverse direction, multiply by 200,000.

• ✓1 µg = 0.001 mg = 1/1,000,000 g.
• ✓Some older labels write "mcg" instead of µg — both mean the same thing.
• ✓For very small doses prefer µg to avoid decimal confusion (0.025 mg vs. 25 µg).

• ✗Treating mcg and mg as equivalent on older prescription pads.
• ✗Typing "mg" when the intended unit is "µg" — a 1000× overdose.
• ✗Reading µg as g without the prefix — a 1-million-fold error.

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

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)