Ounce conversions

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What is ounce?

The international avoirdupois ounce (or simply "ounce") is a unit of mass in the Imperial and US customary systems of units equal to 0.028349523125 kilograms (1 oz = 0.028349523125 kg), the base unit of mass in the International System of Units (SI). It is also equal to 28.349523125 grams (g), or 28,349.523125 milligrams (mg) or 28.349523125x106 micrograms (μg) (SI units of mass), or 0.0625 pounds (lb), or 0.9114583 troy ounces (oz t) or 437.5 grains (gr), which are US customary / Imperial units of mass.

The ounce definition varies depending on the system of units used, as follows:

  • The avoirdupois ounce (or simply "ounce"), equal to 28.349523125 grams (g) or 0.0625 pounds (lb)
  • The troy ounce, equal to 31.1034768 grams (g) or 0.0685714286 pounds (lb)
  • The Apothecaries' ounce, equal to 31.1034768 grams (g) or 0.0685714286 pounds (lb)
  • The Dutch metric ounce, equal to 100 grams (g) or 0.220462262 pounds (lb)
  • The Spanish ounce, equal to 28.75 grams (g) or 0.0633829004 pounds (lb)
  • The Chinese metric ounce, equal to 50 grams (g) or 0.110231131 pounds (lb)
  • The Maria Theresa ounce, equal to 28.0668 grams (g) or 0.0618767022 pounds (lb)

The ounce is commonly used as a unit of mass / weight in the United States and the United Kingdom.

The abbreviation "oz" for ounce comes from the old Italian word "onza".





Also called:

ounce (plural: ounces, symbol: oz)