In alcohol, proof is a way to show how strong a drink is. In the U.S., proof = 2 × ABV (alcohol by volume), so 40% ABV = 80 proof and 50% ABV = 100 proof.

Quick scoop

  • Higher proof = more alcohol in the bottle.
  • The term is used mostly for spirits like vodka, whiskey, and rum.
  • A common example is 80 proof vodka , which is 40% ABV.

Why it matters

Proof helps you compare the strength of drinks and understand how quickly they may affect you. If you want, I can also explain the difference between proof, ABV, and “cask strength” in one simple chart.