It used to be the "Fujita Scale," but now it is known as the "EF - Enhanced Fujita Scale." The same degrees are still used from 0-5 though, I will state them each.
EF 0 = 65-85 mph winds; minor damage, some roof damage, shallow trees knocked over, etc.
EF 1 = 86-110 mph winds; moderate damage, roofs stripped, mobile homes turned over, windows broken
EF 2 = 111-135 mph winds; cars lifted off the ground, considerate damage, roofs torn off houses, large trees uprooted
EF 3 = 136-165 mph winds; stories of well constructed houses totalled, trains and big rigs overturned, heavy cars thrown off ground, severe damage
EF 4 = 166-200 mph winds; devastating damage - houses and whole frame houses completely leveled, cars thrown and small missiles generated
EF 5 = >200 mph winds; extreme damage, houses and frames swept away, steel enforced concrete structures badly damaged, cars picked up and thrown around like toys
Hope this helps!