Converting Between Units — Data Storage and Compression | IGCSE Computer Science

Exam Frequency Analysis

Past paper frequency (2018 to 2024)

This topic accounts for approximately 4% of your exam marks.

stable

Rare

Stable4%

File size calculations and lossless vs lossy compression are regular 3 to 4 mark questions.

The standard rules are simple once you remember the two factors:

Bits ↔ bytes: multiply or divide by 8 (because 1 byte = 8 bits).
Bytes ↔ KiB ↔ MiB ↔ GiB: multiply or divide by 1024 between adjacent units, as the syllabus requires.

Going up a unit (smaller → larger) means dividing. Going down a unit (larger → smaller) means multiplying.