How To Convert Weight Measurements

Weight is one of the most commonly used and measured physical properties of objects. Due to the different conventions all over the world, though, it might be very difficult to convert from one system to another. For instance, you might be applying for a driver's license in another part of the world, and the form requires you to write your weight in kilograms, but you only know your weight in pounds. Or how about buying ingredients for a recipe that calls for a few ounces of spices, but the market's weighing scale uses grams?

Converting weight measurements within one system might be easy enough, but converting across different systems of measurement needs a bit more work. The two most commonly used systems in the US are the Avoirdupois and the metric systems.

Here's how you convert weight measurements.

Avoirdupous System

  • Twenty seven grains is equivalent to one gram.
  • Sixteen grams is equivalent to one ounce (oz.).
  • Sixteen ounces is equivalent to a pound (lb.).
  • A hundred pounds is equivalent to one short hundredweight.
  • Twenty short hundredweight is equivalent to one short ton.
  • To put it into perspective:
  • 1 short ton = 20 short hundredweight = 2,000 pounds = 32,000 ounces = 512,000 drams = 13,824 000 grains

The Metric System

The metric system involves dividing the units into multiples of 10. This makes it easier to convert from one unit to another by simply moving the decimal point either left or right. It also involves the use of standard prefixes that denote the multiple, based on the base unit, which is the gram. For instance, "kilo" means one thousand. "Milli" means one-thousandth.

  • Ten milligrams is equivalent to one centigram.
  • Ten centigrams is equivalent to one decigram.
  • Ten decigrams is equivalent to a gram.
  • Ten grams is equal to 1 decagram.
  • Ten decagrams is equivalent to one hectogram.
  • Ten hectograms is equivalent to one kilogram.

To compare:

1 kilogram = 10 hectograms = 100 decagrams = 1,000 grams = 10,000 decigrams = 100,000 centigrams = 1,000,000 milligrams

US to Metric Conversions

  • An ounce is equivalent to 28 grams. A gram is equal to 0.035 ounce.
  • One pound is equivalent to 0.45 kilograms. One kilogram is equivalent to 2.2 pounds.
  • A short ton is equivalent to 907 kilograms.

If you don't want to convert measurements using the long hand method, you may also try using Web sites that have free converters. Using these sites is quite easy since you can just select the base unit and the unit you want the value to be converted to. The Web site online Conversion ( can help you convert weight values but also distance, time and temperature. If you find the need to use weight measurements when offline, though, you can try downloading converters for your mobile phone or smartphone, such as Weight Converter for the iPhone. In most cases though, you probably need to remember only one cross-system conversion, such as the kilogram to pound conversion, which is 1 kg = 2.2 lbs. Since the metric system uses multiples of tens, you can easily convert kilogram measurements into its equivalents.


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