The 1.5 liter is the right lunch box for most people

The 1.5 liter lunch box is the right starting point for most people — it holds roughly 600 to 900 calories of normal packed food.

The math is simple: one liter of typical cooked food (rice, meat, veg, leftovers) lands around 600–900 calories depending on how dense it is. A 1.5L box gives you room for a solid lunch without being bulky. If you’re an average adult eating a 500–800 calorie midday meal, that’s your box.

Size down to 1L if your lunch is light — around 400–500 calories — or if you mostly eat salads and vegetables. Size up to 2L only if you’re actively bulking, doing physical work, or your lunch is genuinely your biggest meal of the day at 900+ calories.

The common mistake is choosing by appetite alone. Appetite tells you volume; calories come from density. A big eater with calorie-dense food (pasta, cheese, meat) needs a smaller box than a light eater who packs mostly greens. When in doubt, pack your normal lunch in whatever container you already own, measure it once, and buy the size that fits.

Measure your real lunch one time and the guesswork disappears.