Metal rulers are the only ones that survive a backpack

Metal rulers are the way to go if you need something that won’t snap in a backpack.

Plastic rulers crack, splinter, or snap clean in half the first time a textbook lands on them. Wooden ones aren’t much better — they chip and split at the ends. Metal will bend if you abuse it, but you can usually bend it back into shape. That’s a lot more than you can say for the other options.

When you’re picking a metal ruler, go for steel, not aluminum. Aluminum is lighter but softer, so it’ll warp and stay warped. A standard steel ruler, 12 or 18