Centigram — Definition, Formula & Examples
A centigram is a metric unit of mass equal to one hundredth (1/100) of a gram. It is a very small unit, useful for measuring lightweight items like tiny amounts of powder or medicine.
The centigram (symbol: cg) is a unit of mass in the metric system defined as grams, or equivalently kilograms. The prefix "centi-" denotes a factor of , following the same pattern as centimeter and centiliter.
Key Formula
Where:
- = centigrams
- = grams
- = milligrams
How It Works
The metric system uses prefixes to scale a base unit up or down by powers of ten. For mass, the base unit is the gram. The prefix "centi-" means one hundredth, so 1 centigram equals 0.01 grams. To convert centigrams to grams, divide by 100. To convert grams to centigrams, multiply by 100. You can also move between neighboring metric units (milligrams, centigrams, decigrams) by shifting the decimal point one place.
Worked Example
Problem: A scientist measures out 350 centigrams of a substance. How many grams is that?
Set up the conversion: Since 1 cg = 0.01 g, multiply the number of centigrams by 0.01.
Answer: 350 centigrams equals 3.5 grams.
Why It Matters
Understanding centigrams helps you read metric measurements in science labs and on medication labels. Pharmacists and chemists often work with very small masses, and being comfortable converting between milligrams, centigrams, and grams prevents dosing or measurement errors.
Common Mistakes
Mistake: Confusing "centi-" (1/100) with "milli-" (1/1000) and incorrectly stating that 1 cg = 0.001 g.
Correction: Remember that "centi-" means hundredths: 1 cg = 0.01 g. "Milli-" means thousandths: 1 mg = 0.001 g. A centigram is ten times larger than a milligram.