I state the dimensions of the the boxes here: https://magneticstashbox.com/detailed-information-stash-box-magnetic but sometimes more information is needed especially for European customers.
To give a better idea of the interior space, I used 2 cups (made sure by using a measuring cup that they held 1 cup of water) and placed inside a XXL and closed and snapped the lid with no issue.
Here are the pics. 2 cups = 473.17647 grams according to online calculation websites. Keep in mind that the exterior of these ceramic cups take up space as well as the space between cups.
I’m sure some of the math brains can look at the dimensions and give an exact but I’m more visual.
Internal 7.9 ” X 3.8 ” X 3.6 ”