# Big-O Notation

Big-O Notation refers to how complex code is.

## What is **Big-O Notation**?

**Big-O Notation** refers to how complex code is.

There are 2 parts that make up Big-O complexity.
1. How long it takes code to execute
2. How much storage space is required for the process (or calculation)

Level: Journeyman · [More OOP terms at this level](https://www.ask-codey.com/glossary/subjects/oop/journeyman)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/big-o-notation