Power of 10 Prefixes
Scientific prefixes are shorthand for powers of 10. They help us write very large or very small numbers more clearly. Instead of writing 0.000000001 m, we can write 1 nm.
| Prefix | Symbol | Power of 10 | Example |
|---|---|---|---|
| pico | p | 10-12 | 1 picometre = 1 × 10-12 m |
| nano | n | 10-9 | 1 nanosecond = 1 × 10-9 s |
| micro | µ | 10-6 | 1 microgram = 1 × 10-6 g |
| milli | m | 10-3 | 1 millimetre = 1 × 10-3 m |
| centi | c | 10-2 | 1 centimetre = 1 × 10-2 m |
| kilo | k | 103 | 1 kilometre = 1 × 103 m |
| mega | M | 106 | 1 megawatt = 1 × 106 W |
| giga | G | 109 | 1 gigabyte = 1 × 109 bytes |
| tera | T | 1012 | 1 terajoule = 1 × 1012 J |
How to use them
- Move the decimal point by the number of powers in the prefix.
- If the prefix is smaller than the base unit, the number gets bigger.
- If the prefix is larger than the base unit, the number gets smaller.
- Use the exponent to count how many zeros to move.
Example: 3.2 km = 3.2 × 10^3 m = 3200 m.
Example: 4.5 nm = 4.5 × 10^-9 m = 0.0000000045 m.
Quick memory tip: Going down the table from pico to tera, each step is a factor of 1000 or 10^3.
The larger the prefix, the bigger the value it represents.