1. Unit 1 1.7 Units of Measurement

2. What you need to learn:
Students need to learn the units of measurement used in IT
bit, nibble, byte
• metric (kilo, mega, giga, tera, peta)
• binary (kibi, mebi, gibi, tebi, pebi)
• comparison in sizes between metric and binary measurements. e.g. 1 kilobyte = 1000 bytes vs 1024 bytes

3. Bit, nibble, byte

4. Measurements

5. Metrics metric (kilo, mega, giga, tera, peta) Name Symbol Decimal peta
tera T
giga G
mega M
kilo k
1000

6. Binary
binary (kibi, mebi, gibi, tebi, pebi)
binary prefix multipliers

7. Comparison between metric and binary
1 kilobyte = 1000 bytes vs 1024 bytes
Computers refer to 1 kilobyte as 1024 bytes, because 1024 = 210 (computers work in two symbols, on and off switches 0 and 1); whilst most humans refer to 1 kilobyte as 1000 bytes, because it is much easier to work with round numbers like this.