Dimensional analysis is one of those quiet little superpowers in engineering and physics. It’s basically the art of checking whether your equations make sense by looking only at the types of quantities involved — not the numbers.

Plain version:

It’s a method where you look at the dimensions of physical quantities — like
• Length → L
• Time → T
• Mass → M
• Temperature → Θ
and so on — and you make sure your equations don’t do something absurd like adding metres to seconds.

Think of it like grammar for physics:
you can’t add “cat + yesterday”, and you also can’t add “metres + kilograms”.

Dimensional analysis lets you:
• Check if an equation is valid
• Convert units properly
• Derive relationships between variables
• Spot errors without doing full calculations

Example in action:
Speed = distance / time
Its dimensions are: L / T
So if someone writes speed = distance × time, the dimensions become L × T — which is nonsense.