Weight Converter●
From nanograms to tonnes. Convert metric, imperial and specialist weights with clear results.
Weight
Use a decimal point, for example 2.54. Scientific notation works too: 1e3.
Common conversions
Pick an example to startAll equivalent units
The same value, in every supported unit.
Choose the right kind of ounce.
Standard and troy ounces measure different masses. Carats here measure gemstone mass; fluid ounces belong in Volume Converter. US short tons, UK long tons and metric tonnes are labelled separately.
- 1 kg
- 1,000 g
- 1 lb
- 0.45359237 kg
- 1 st
- 14 lb
Calculation details & precision
Weight conversions use kilograms as the base mass unit. One pound is exactly 0.45359237 kg and a stone is 14 lb. Metric tonnes, US short tons and UK long tons are separate units. Troy ounces and standard ounces use different definitions.
Automatic displays up to 12 significant digits. Choose 2, 4 or 6 decimal places in Precision for a shorter result. Displayed results are rounded; very large or small values use scientific notation.
Common questions
What is the difference between an ounce and a fluid ounce?
An ounce here measures mass. A fluid ounce measures volume and is not interchangeable with it. Converting volume to mass also requires the substance’s density.
How are pounds and tonnes defined?
One international avoirdupois pound is exactly 0.45359237 kilograms. One metric tonne is 1,000 kg; a US short ton is 2,000 lb and a UK long ton is 2,240 lb.
Are standard and troy ounces the same?
No. A standard avoirdupois ounce is 28.349523125 grams. A troy ounce, used for precious metals, is 31.1034768 grams. Use the explicitly labelled Troy ounces option for that unit.
What do stone and carat mean?
One stone is 14 pounds. A metric carat measures mass and equals 0.2 grams; it is different from karat, which describes gold purity.