EF Scale

The enhanced Fujita scale (EF SCALE) is the most common way of rating a tornado. it is rated based off of damage not windspeed. 

ef0 65-86 mph (minor)

ef1 86-110 mph (damaging)

ef2 110-135 mph (significant)

ef3 135-165 mph (Destructive)

ef4 165-200mph (EXTREME)

ef5 200+mph (Catastrophic)