Capacity depends on appetite, not age

A school-aged child typically needs 500–800ml of lunch box capacity, while most adults are comfortable with around 1 liter. But that’s a starting point, not a rule.

The real question is what fits their actual meal, not their grade. A 6-year-old who eats half a sandwich, fruit, and a yogurt is fine with a compact 500ml box. A teenager who comes back for seconds at dinner might need the same 1 liter box as you.

Also, capacity doesn’t equal volume that’s all usable. Bento-style boxes with tight compartments lose space to dividers, but they’re often better because they stop a sandwich from turning into crumbs. A plain open box can hold more, but you’ll probably pack less variety.

If you’re buying for a kid between roughly 8 and 12, look at 700–800ml. Younger than that, 400–600ml is plenty. For an adult, a single 1 liter container covers a normal work lunch; if you’re a serious leftover packer, get 1.2L or a lunch bag with a separate snack box.

The sizing guide helps, but the best test is to pack one day’s lunch, see if it fits without stuffing, and adjust from there.