# How to measure the volume of a Backpack?

Measuring the volume of a backpack is easy and requires no calculations or complicated formulas.
Some people will use the formula volume = length x width x height, but that’s actually not true. This is because this formula is used to measure the volume of a box.

However, most backpacks are not in the shape of a box. Instead, backpacks are usually irregularly shaped. More importantly, the size of the backpack is not our concern. What we want to know is the storage capacity of the backpack, which is the capacity of the things that can be put in the backpack.
The method I’ll show you below is very easy to use and is used by most and outdoor gear manufacturers to measure the volume of their packs.

### ① First, you need a lot of small balls or beans

We use ping pong balls with a diameter of 40mm, you will need a lot.

### ② Fill your backpack with ping pong balls

Fill the backpack with ping pong balls until it is completely full.
Some will only fill the main compartment, while others will also include outer pockets. There really is no standard. In my opinion I would also include the outside pockets as they also help with storage capacity.

### ③ Count how many ping pong balls you have loaded

You can get the exact volume of your backpack by checking the number of ping pong balls you fill.
You are using a table tennis ball. The volume of the table tennis ball is about 33.5cm³, and 1L can hold about 30 table tennis balls. The backpack can hold 300 table tennis balls, so the volume of the backpack is about 30L. It’s straight forward, right? Of course, we don’t buy ping pong balls in bulk just to measure the size of our backpacks. This is just one of many ways.