Big-O notation is the mathematical notation that helps analyse the algorithms to get an idea about how they might perform as the input grows. The image below explains Big-O in a simple way without using any fancy terminology. 

[![](/guides/big-o-notation.png)](/guides/big-o-notation.png)

Here is the [original tweet](https://twitter.com/kamranahmedse/status/1235708842610212864) where this image was posted.