Tornado scale converter
Convert tornado ratings between the Enhanced Fujita scale, the original Fujita scale, TORRO and wind speed.
That's 1.11× as strong as a strong EF2 tornado, while a violent EF4 tornado is 1.35× stronger.
What it means
How strong is that tornado?
EF uses three-second gusts and the old F-scale fastest-quarter-mile winds, so the same rating number means different speeds. Ratings are estimated from damage.
Every unit
That tornado on every scale
Learn
Three things worth knowing
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65, 86, 111, 136, 166, 201
EF0 to EF5 start at these gusts in mph. In km/h: 105, 138, 178, 218, 266 and 322.
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Mr. Tornado
Tetsuya “Ted” Fujita of the University of Chicago mapped tornado damage from the air and published his F-scale in 1971. The Enhanced version replaced it after engineers found F3–F5 winds were set too high.
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F3 and EF3 differ
An old F3 meant 158–206 mph; an EF3 is 136–165 mph. Old and new ratings describe similar damage with different speeds.
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Background
About tornado scales
Nobody can put an anemometer in a tornado’s path, so tornadoes are rated after the fact, from the damage. The Enhanced Fujita scale, used in the US since 2007 and in Canada since 2013, links 28 kinds of damage to estimated three-second gusts: EF0 from 65 mph up to EF5 above 200 mph.
Its predecessor, Ted Fujita’s F-scale of 1971, overestimated the winds of strong tornadoes. Britain and much of Europe use TORRO, a formula that lines up with Beaufort.