How weight and mass conversions work
In everyday commerce, cooking, fitness, and shipping, "weight" refers to mass measured against exact international standards anchored to the kilogram (kg):
- Metric units: 1 metric ton (tonne) = 1,000 kg; 1 kilogram = 1,000 grams (g); 1 gram = 1,000 milligrams (mg) = 1,000,000 micrograms (µg).
- Imperial & US avoirdupois units: 1 pound (lb) = 0.45359237 kg exactly; 1 pound = 16 ounces (oz); 1 stone (st) = 14 pounds (6.35029318 kg).
- Tons compared: A metric tonne is 1,000 kg (~2,204.62 lb), a US short ton is 2,000 lb (907.185 kg), and a UK imperial long ton is 2,240 lb (1,016.047 kg).
- Jewelry & precious metals: Diamonds and gemstones use metric carats (1 ct = 0.2 g), while gold, silver, and platinum bullion are quoted in troy ounces (1 oz t = 31.1034768 g).