Centi- — Definition, Formula & Examples

Centi- is a metric prefix that means one hundredth, or 1/100. When you put "centi-" in front of a unit, you divide that unit into 100 equal parts — for example, a centimeter is one hundredth of a meter.

The prefix "centi-" denotes a factor of $10^{-2}$ (0.01) in the International System of Units (SI). Attaching it to any base unit produces a derived unit equal to one hundredth of that base unit.

Key Formula

1 \text{ centi-unit} = \frac{1}{100} \text{ base unit} = 10^{-2} \text{ base unit}

Where:

$\text{centi-unit}$ = The unit with the centi- prefix (e.g., centimeter)
$\text{base unit}$ = The original metric unit (e.g., meter)

How It Works

Place "centi-" before a metric unit to create a smaller unit that is exactly 100 times smaller. To convert from the base unit to centi-units, multiply by 100. To convert from centi-units back to the base unit, divide by 100. The most common example is the centimeter: there are 100 centimeters in 1 meter. You may also encounter centiliters (1/100 of a liter) or centigrams (1/100 of a gram), though these are less common in everyday life.

Worked Example

Problem: A ribbon is 3 meters long. How many centimeters is that?

Recall the meaning: Centi- means 1/100, so 1 meter = 100 centimeters.

1 \text{ m} = 100 \text{ cm}

Multiply: Multiply the number of meters by 100.

3 \times 100 = 300

Answer: The ribbon is 300 centimeters long.

Why It Matters

Centimeters are one of the most frequently used units in school and daily life — rulers, body height, and paper sizes all use them. Understanding the centi- prefix helps you convert quickly between centimeters and meters on science and math assignments.

Common Mistakes

Mistake: Confusing centi- (1/100) with milli- (1/1000)

Correction: Centi- divides the base unit into 100 parts, while milli- divides it into 1,000 parts. A centimeter is 10 times larger than a millimeter.