This is the bead-filling method that we have perfected over many years as a bag factory, yielding consistently reliable results. While based on the ASTM F2153-07 Standard Test Method for Measurement of Backpack Capacity, we have made specific adjustments to better suit our needs.

3 Easy Steps to measure the backpack volume.

1) Prepare the Filling Material
We recommend using small plastic balls with a diameter of 20mm, though alternatives like Ping Pong balls or dried beans can also be used. Ensure you have a sufficient quantity to fill the entire bag.

2) Fill the backpack using a measuring cup

Begin by filling the backpack with the balls or beans, using a measuring cup for precision, until it is completely full. Some prefer to fill only the main compartment, as suggested by ASTM F2153, while others include the outside pockets. Although there is no universal standard for this, I recommend including the outside pockets, as they contribute to the overall storage capacity.

3) Count the Cups of Balls/Beans

Determine the backpack’s volume by counting the number of cups of balls or beans used to fill it. For instance, if you’re using a 1L measuring cup and the backpack holds 20 cups, the volume is 20L.

This method for measuring backpack capacity is both accurate and user-friendly.