# Decigram

A decigram (dg) is a unit of weight/mass in the International System of Units (SI), the modern form of the metric system of measurement.

1 decigram = 0.0001 kilograms

1 decigram = 0.1 grams

Below are some relationships between decigrams and units of mass in the US customary system of measurement.

1 decigram = 0.00022 pounds

1 decigram = 0.00353 ounces

The decigram is not a widely used unit of mass. It is smaller than the gram and kilogram, likely the two most commonly used units of mass in SI, and is slightly larger than the milligram. Outside of scientific contexts such as a laboratory setting, where precision is often important, decigrams are not a widely used unit of measurement. This is likely because it is only smaller than a gram by 1 power of 10, and grams have, and continue to be, a widely used unit of mass, so in most cases where a decigram could be used, the gram is more likely to be used instead.

## SI prefixes

The International System of Units (SI) makes use of SI prefixes (milli-, centi-, kilo-, etc.) to denote multiples or submultiples of a base unit that are related by a power of 10. The base unit of mass in SI is the kilogram. The kilogram is unique as a base unit in that it is the only base unit that already has an SI prefix, kilo-, indicating that 1 kilogram is 10^{3} grams. All other base units in SI such as meters, seconds, moles, etc., do not have prefixes.

Since SI does not allow for the use of multiple prefixes (e.g. "kilomilligram") to modify a base unit, prefixes are added to the gram, rather than kilogram, to denote different multiples or submultiples of mass.

1 decigram = 10^{-4} kilograms

1 decigram = 10^{-1} grams

1 decigram = 10^{1} centigrams

1 decigram = 10^{2} milligrams

Remembering SI prefixes and what power of 10 they represent is helpful because it allows us to choose the most appropriate unit for whatever is being measured. For example, a cup of coffee may contain 1 dg (100 mg) of caffeine. If its mass were measured in kilograms instead of decigrams, the amount of caffeine in the cup would be written as 0.0001 kilograms, which is more difficult to work with than 1 decigram, particularly when performing any calculations.

It is also important to be able to convert between various measurements of mass in different systems, particularly from US customary units to SI, since SI is the standard used throughout most of the world.

Examples

Convert the following measurements to decigrams and kilograms.

1. 32 pounds:

There are 0.00022 pounds in 1 decigram, or 4535.924 decigrams in 1 pound, so:

32 × 4535.924 = 145,149.6 dg

145,149.6 × 10^{-4} = 14.515 kg

2. 112 ounces:

There are 0.00353 ounces in a decigram, or 283.495 decigrams in 1 ounce, so:

112 × 283.495 = 31,751.44 dg

31,751.44 × 10^{-4} = 3.175 kg