Flat bento boxes beat lunch bags in school cubbies

The best slim lunch boxes for elementary school cubbies are flat bento boxes—think PlanetBox or LunchBots—not insulated bags, because flat is what actually fits.

I measured this problem the hard way. Cubbies are usually only about six inches deep and the opening is tight. Most lunch bags, even “slim” ones, are round-ish when full and eat the whole space. A flat bento box slides in like a tray and leaves room for a jacket or folder on top.

PlanetBox is my pick if you want to spend once and be done. It’s stainless, roughly 10 inches by 7 inches, and only about 1.75 inches thick. LunchBots makes a similar flat stainless option for less money. Yumbox is the best cheaper alternative and comes in a very shallow 1.5-inch profile, though the latches can frustrate little fingers. Skip the Bentgo Kids for this specific problem—it’s a good box, but it’s noticeably thicker and fights you in a shallow cubbie.

Whatever you pick, buy one that’s wider than it is tall. That shape is the whole trick.

Your kid’s backpack gets thinner too, which is a bonus nobody talks about.