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Weather-Corrected ET Calculator
Correct your ET to standard sea-level air
A weather-corrected ET is your elapsed time adjusted to standard sea-level air, so runs made in different weather can be compared fairly.
Formula: Corrected ET = ET × (air density ratio)^⅓ — power follows air density; ET follows power by the cube-root law
What this number means
This corrects a run to standard sea-level air so passes made on different days can be compared honestly. It removes most of the weather from the comparison, leaving the changes you actually made to the car.
What to change next
Correct your logbook runs before judging any tuning change — a gain that disappears after correction was just better air. If corrected performance is genuinely improving, keep moving in that tuning direction.
Worked example
An 11.60 run made at 3,000 ft density altitude corrects to ≈ 11.26 at sea level.