For five-day meal prep, airtight glass beats everything.

The best lunch boxes for prepping five identical lunches on Sunday are individual glass containers with gasket-sealed, clip-lock lids — the kind from Prep Naturals, Pyrex Snapware, or Glasslock.

The key is the seal, not the glass. A rubber gasket pressed down by four clips makes the container genuinely airtight. That’s what keeps Thursday’s lunch from tasting like it’s been sitting next to Tuesday’s. Plastic lids without gaskets leak air, and you’ll notice it by day three.

Skip bento-style compartment boxes for this. They look nice in the Instagram photo, but compartmentalized trays rarely seal well, and the open air between sections dries out or sogs your food faster. If you really want separation, use the silicone muffin liners inside a plain glass box — cheaper and easier to clean.

Get the 3-cup size. It fits a normal lunch — protein, starch, vegetable — without forcing you to pack a sad, half-empty container. Most cooked meals hold up fine for 4-5 days in a truly airtight glass container in the fridge. If you’re prepping raw fish, that’s a different problem, and no lunch box will fix it.

One thing worth paying for: oven-safe glass and a lid that doesn’t warp in the dishwasher. The cheap ones leak or crack by week six.

Your Friday self will not regret the extra twelve bucks.