Convert Kilogram to Carat (kg → ct)

Converting kilograms 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 kilograms

   Start with the number of kilograms (kg) you want to convert.
2. 2
   Multiply by 5,000

   The conversion factor from kg to ct is 5,000. 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 kilograms by 5,000. For the reverse direction, multiply by 0.0002.

• ✓1 kg ≈ 2.205 lb. For quick estimates, double the kg figure and add 10%.
• ✓Body weight is best measured first thing in the morning, after using the bathroom but before breakfast.
• ✓The kg is the only SI base unit whose name contains a prefix — a historical quirk of the metric system.

• ✗Confusing mass (kg) with weight-force (newtons) in physics problems.
• ✗Using 2 instead of 2.205 when converting kg to pounds — the 2.5% error matters for airline luggage.
• ✗Writing Kg instead of kg — the correct SI abbreviation is lower-case kg.

What is the Kilogram?

The kilogram is the base SI unit of mass. Since May 2019, it has been defined by fixing the numerical value of Planck's constant to exactly 6.62607015 × 10⁻³⁴ joule-seconds — a major shift from the previous definition based on a physical platinum-iridium artifact (the International Prototype Kilogram or 'Le Grand K') stored at the BIPM near Paris since 1889. This redefinition links the kilogram to a fundamental constant of nature, making it reproducible by any sufficiently equipped laboratory. The kilogram is the global standard for body weight (most countries quote weight in kilograms), grocery sales, scientific measurements, and engineering. One liter of pure water at 4°C has a mass of almost exactly 1 kg — a coincidence designed into the original 1795 definition. The kilogram relates to the gram (1,000 g = 1 kg), the metric ton (1,000 kg = 1 t), and the pound (1 kg ≈ 2.205 lb).

• Human body weight in most of the world
• Grocery and retail food quantities in Europe
• Scientific and engineering mass measurements

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)