Get a wide-mouth thermos for soups.

The best leak-proof lunch box for soups or curries is a wide-mouth food jar — the kind you’d take camping. A Zojirushi, Thermos, or Hydro Flask will survive being tossed sideways in a backpack without leaking a drop. They also keep things hot (or cold) for hours, which is a bonus.

Regular plastic or glass containers with snap-lock clips and silicone gaskets can be leak-proof too — Glasslock is a solid choice — but they take a perfect seal to work. One stray grain of rice or a chip in the gasket and you’ve got a bag full of tikka masala. The screw-on lids on food jars simply don’t fail that way.

Downside: a thermos isn’t microwave-safe, so if you need to reheat at work, you’ll be decanting into a bowl. That’s fine. If you absolutely need something that goes from fridge to microwave to bag in one piece, get a Glasslock with the locking clips and test it with water first.

For soup and runny curries, don’t fight the physics. Get the jar. It’s the one lunch container that doesn’t make you walk to the car with your fingers crossed.