Hurricane category converter
Convert a hurricane category to its sustained wind speed, or a wind speed in mph, km/h or knots to its Saffir–Simpson category.
That's 1.5× as strong as a Category 1 hurricane, while Hurricane Katrina at landfall (2005) is 1.13× stronger. Its wind pushes about 2.3× as hard as the weakest hurricane’s.
What it means
How strong is that storm?
One-minute sustained winds, US National Hurricane Center bands. A category number between two whole ones places the wind within that band.
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That storm in every unit
Learn
Three things worth knowing
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74, 96, 111, 130, 157
The categories start at these speeds in mph. In km/h: 119, 154, 178, 209 and 252.
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An engineer and a meteorologist
Structural engineer Herbert Saffir described damage by wind speed in 1969; Robert Simpson, director of the National Hurricane Center, added the categories in the 1970s.
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Damage grows faster than speed
Wind force goes with the square of speed, so a 157 mph Category 5 pushes 4.5 times harder than a 74 mph Category 1, not twice.
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Background
About the Saffir–Simpson scale
The Saffir–Simpson Hurricane Wind Scale sorts hurricanes into five categories by their highest one-minute sustained wind: 1 from 74 mph (119 km/h), 2 from 96, 3 from 111, 4 from 130 and 5 from 157 mph (252 km/h). Category 3 and up are “major hurricanes”.
The scale rates only wind. Storm surge and rain, which cause most deaths, are not part of it: a slow Category 1 can flood more than a fast Category 4.