--- title: "Highway Speed and EV Efficiency: What It Costs to Drive Fast" description: "Drag rises with the square of speed. In our illustration, a 300-mile trip at 75 instead of 65 mph costs $8.79 more at public-charger prices. See the math." url: https://evchargecosts.com/guides/highway-speed-and-ev-efficiency/ updated: 2026-10-26 --- # Highway Speed and EV Efficiency: What It Costs to Drive Fast Driving faster costs more because aerodynamic drag grows roughly with the square of speed. In our illustration, a typical EV that uses 33.5 kWh/100 mi at 60 mph needs about 42.9 at 75 mph, so a 300-mile trip costs **$3.55 more at home prices** (18.16¢/kWh) or **$8.79 more** at $0.45/kWh public charging than at 65 mph. By [EV Charge Cost Editorial Team](https://evchargecosts.com/about/). Published September 28, 2026, updated October 26, 2026. ## Why speed matters more in an EV At low speeds most of an EV's energy goes into rolling resistance, drivetrain losses and accessories. As speed rises, aerodynamic drag takes over. Drag force grows roughly with the square of speed, and since energy per mile equals force times distance, the energy spent on drag per mile also grows with the square of speed. Going from 60 to 75 mph raises that part of the bill by (75 ÷ 60)² = 1.56×. Gas cars face the same physics, but their engines waste so much energy as heat at every speed that the change is less visible. An EV's drivetrain is efficient enough that drag becomes a large share of highway consumption. ## An illustration, speed by speed To show the scale, take a car that uses 33.5 kWh per 100 miles at a steady 60 mph, and assume half of that goes to aerodynamic drag and half to everything else. These shares are an illustration, not a measurement; the real split depends on the car's shape, frontal area, tires and weather. The non-drag part is held constant and the drag part scales with speed squared. **Illustration: consumption and cost by steady speed (home 18.16¢/kWh, public $0.45/kWh)** | Speed | kWh/100 mi | vs 60 mph | Per 100 mi, home | Per 100 mi, public | | --- | --- | --- | --- | --- | | 55 mph | 30.8 | −8% | $5.60 | $13.87 | | 60 mph | 33.5 | +0% | $6.08 | $15.08 | | 65 mph | 36.4 | +9% | $6.61 | $16.38 | | 70 mph | 39.5 | +18% | $7.18 | $17.80 | | 75 mph | 42.9 | +28% | $7.79 | $19.31 | | 80 mph | 46.5 | +39% | $8.45 | $20.94 | Range moves the other way. In this illustration, a car with 300 miles of range at 60 mph would get about 234 miles at 75 mph and 216 at 80 mph. ## Is the time saved worth it? On a 300-mile trip, 75 mph instead of 65 saves about 37 min of driving time, ignoring traffic and stops. In the illustration it costs $3.55 more in home electricity and $8.79 more if the energy comes from fast chargers at $0.45 per kWh. That is about $14.29 per hour saved at public prices. There is a second cost that does not show up in dollars. Higher consumption means more or longer charging stops, which can eat into the time you saved. On long trips, a moderate speed that lets you skip one stop can be both cheaper and faster. See [road trip charging costs](https://evchargecosts.com/guides/road-trip-charging-cost-estimate/) for planning a whole trip. ## Try the math on your own car You can adapt the illustration to your car. Note your consumption on a calm day at a steady speed you normally drive, then estimate a faster speed with: new kWh = old kWh × (share not from drag + share from drag × (new speed ÷ old speed)²). If you do not know the drag share, run it with a low and a high guess to get a range. A fair check is to drive the same stretch of road at two speeds on the same day and compare the trip computer readings. ## Why your commute may beat the EPA number The EPA combined rating blends city and highway driving. Around town, regenerative braking recovers energy and drag is small, so many EVs do better than their rating in stop-and-go traffic and worse at sustained highway speeds, the reverse of most gas cars. See [regenerative braking and range](https://evchargecosts.com/guides/regenerative-braking-and-range/). ## Practical steps - Use adaptive cruise at a steady speed; repeated speed-ups cost energy. - Remove roof boxes and racks when not in use; they add frontal area and drag. - Check tire pressure before long trips. - Headwinds act like extra speed, so expect higher consumption on windy days. To put your own highway consumption into dollars, enter it in the [charging cost calculator](https://evchargecosts.com/). ## Run your own numbers - [Charging cost calculator](https://evchargecosts.com/) - [EV vs gas calculator](https://evchargecosts.com/ev-vs-gas/) - [Charging time calculator](https://evchargecosts.com/charging-time/) - [Cost in your state](https://evchargecosts.com/states/) - [How we calculate](https://evchargecosts.com/methodology/) ## Related guides - [What kWh per 100 Miles Means (and How It Relates to MPGe)](https://evchargecosts.com/guides/what-kwh-per-100-miles-means/) - [How Much Does It Cost to Charge an Electric Truck?](https://evchargecosts.com/guides/cost-to-charge-an-electric-truck/) - [How Much Does It Cost to Charge an Electric SUV?](https://evchargecosts.com/guides/cost-to-charge-an-electric-suv/) - [The Cheapest Electric Cars to Charge (Most Efficient EVs)](https://evchargecosts.com/guides/cheapest-evs-to-charge/) - [Does Cold Weather Increase EV Charging Cost?](https://evchargecosts.com/guides/cold-weather-ev-charging-cost/) - [What Is MPGe? MPGe Explained for EV Owners](https://evchargecosts.com/guides/mpge-explained/) [All 59 guides](https://evchargecosts.com/guides/) ## Questions people ask ### What is the most efficient speed for an EV? Lower steady speeds use less energy per mile because drag grows with the square of speed. In practice most EVs are most efficient at moderate city or suburban speeds, and consumption rises noticeably above typical highway limits. ### How much more does 80 mph cost than 65 mph in an EV? In our illustration, a typical EV uses about 28% more energy per mile at 80 mph than at 65, which adds about $1.84 per 100 miles at 18.16¢/kWh. Real results vary by car and conditions. --- Source page: https://evchargecosts.com/guides/highway-speed-and-ev-efficiency/ Data: EIA (electricity August 2026, gasoline 2026-10-19), EPA fueleconomy.gov. License: CC BY 4.0.