Tornado EF Calculator
Enhanced Fujita rating and damage from gusts.
What it does
Tornadoes earn EF numbers from wind damage: the Enhanced Fujita scale sorts 3 second gusts into six bands with damage words attached. Surveys rate storms after; estimates band them live.
The tool above takes gust speed in mph or km/h. It returns the EF rating, damage words, and the band.
The default 130 mph lands EF2 with considerable damage in 111-135. The 100 case lands EF1, and 210 lands EF5.
Storm prediction guidance publishes the gust bands with damage indicators surveyors use. Wind engineering research calibrates the same scale behind ratings.
Ratings describe damage, not safety advice: low end twisters still kill the exposed. Warnings, shelters, and sirens rule storms; arithmetic only explains them.
How to use
- Pick mph or km/h.
- Type the gust speed.
- Read EF first.
- Read damage beside it.
- Read the band last.
- Heed warnings always.
Formula
- wind
- 3 second gust in mph.
- EF
- Enhanced Fujita 0 to 5.
Storm Prediction Center Enhanced Fujita guidance fixes the same gust bands with matching damage indicators. Wind engineering research behind the scale calibrates gusts to damage degrees. Metric inputs convert at 1.60934 first; bands read 3 second gusts.
Worked example
Example: 130 mph gust
Imperial defaults: 130 mph.
- Winds: 130 mph 3 second gust.
- Bands: 65-85, 86-110, 111-135, 136-165, 166-200, 200+.
- Rating: 130 sits EF2.
- Damage: considerable damage expected.
- Metric: 209 km/h converts to the same band.
- Tool shows EF2, Considerable damage, 111-135 mph.
Reference table
| Winds | Rating | Damage |
|---|---|---|
| 65 to 85 | EF0 | Light |
| 86 to 110 | EF1 | Moderate |
| 111 to 135 | EF2 | Considerable |
| 136 to 165 | EF3 | Severe |
| 166 to 200 | EF4 | Devastating |
| 200 plus | EF5 | Incredible |
Limits
- Gust bands, not surveys.
- 3s gusts assumed.
- US scale version.
- Warnings outrank arithmetic.
Common mistakes
- Rating by sustained winds.
- Ignoring survey confirmation.
- Downgrading low end killers.
- Mixing F with EF scales.
- Timing shelter by math.
Try it yourself
Quick checks. Answers sit tucked under each question.
100 mph?
EF1 with moderate damage in 86-110.
210 mph?
EF5 with incredible damage at 200 plus.
209 km/h?
EF2 considerable: 209 km/h converts to 130 mph.
40 mph?
Below 65 stays unrated: no EF number.
Questions
Wind bands?
65-85 EF0, 86-110 EF1, 111-135 EF2, 136-165 EF3, 166-200 EF4, 200 plus EF5. Under 65 unrated.
Damage words?
Light, moderate, considerable, severe, devastating, incredible from EF0 to EF5.
Gust or sustained?
3 second gusts at 33 ft. Sustained winds rate hurricanes instead.
Rate live storms?
No, surveyors rate damage indicators after. Wind estimates assign provisional bands.
200 km/h?
Yes, near 209 km/h. Convert first, then band the mph result.
Shelter by math?
No, this screens wind bands. Warnings and shelters rule safety, never arithmetic.