How to Use the EV Highway Speed Range Calculator
An EV's rated efficiency is usually measured around a steady 55 mph. But real highway driving often runs faster than that, and since aerodynamic drag increases with the square of speed, efficiency drops off faster than most drivers expect. Enter your rated efficiency, battery capacity, and target speed, and this calculator applies a speed-based drag penalty to estimate your adjusted efficiency and real-world range.
Gas-powered cars also lose fuel economy at higher speeds, but EVs tend to feel the aerodynamic penalty more directly. Before a long highway trip, it's safer to check your estimated range at your planned speed rather than trusting the full-charge range figure at face value.
Real efficiency is also affected by outside temperature, climate control use, cargo load, and tire pressure, so treat this result as an approximation and build in a margin when planning charging stops.
Frequently Asked Questions
Aerodynamic drag increases with the square of speed, so efficiency loss accelerates sharply as you go faster. EVs tend to feel this more than gas cars, which is why range drops noticeably on the highway.
Outside temperature, climate control use, cargo load, and tire pressure all affect real efficiency. This calculator only models the increase in aerodynamic drag with speed, so treat the result as an approximation and build in a margin.
Keeping a steady speed and avoiding hard acceleration or braking helps. Using adaptive cruise control and removing unnecessary drag sources like roof boxes can also soften the range loss at higher speeds.