About the EV Range Calculator
This EV range calculator estimates how far an electric car will really go on a charge once speed and weather are taken into account. Enter the usable battery capacity, the car’s rated efficiency in kWh per 100 miles, your cruising speed and the outside temperature, and it returns the full-charge range plus the miles you can drive between the state of charge you start at and the reserve you want to keep.
It is meant for road-trip planning, for comparing EVs before you buy and for understanding why your winter range is lower than the window sticker. Higher speed raises energy use because aerodynamic drag grows with the square of speed, and cold weather cuts range because the battery is less efficient and the cabin heater draws power.
The temperature effect is anchored to AAA’s 2019 test, which found a 41% range loss at 20°F and a 17% loss at 95°F with climate control running, versus 75°F. Real results vary by model, heat pump, tyres, wind, elevation and payload, so treat the answer as a planning estimate and keep a buffer.
With the default inputs, the usable range for this trip is 183 mi. Change any value above to recalculate instantly.
How to use the ev range calculator
- 1Enter the usable battery capacity (not the gross figure) in kWh.
- 2Enter the rated efficiency in kWh/100 mi, or divide your Wh/mi reading by 10.
- 3Set your typical cruising speed and the expected outside temperature.
- 4Choose whether you will run the heater or air-conditioning.
- 5Set your starting charge and the reserve you want to arrive with to see trip range.
Formula and method
The rated efficiency is treated as the car’s consumption at a steady 55 mph in mild weather. The speed factor S(v) splits that consumption into three parts: about 5% for accessories (which costs more per mile the slower you go), 50% for rolling and drivetrain losses (roughly constant per mile) and 45% for aerodynamic drag, which scales with the square of speed. At 65 mph S is about 1.17, so the car uses 17% more energy per mile than at 55 mph.
The temperature penalty T is interpolated from AAA’s 2019 test: 0% at 75°F, 41% at 20°F and 17% at 95°F with climate control on, extended linearly beyond those points and capped at 60%. With climate control off we assume 30% of that penalty, because battery chemistry alone causes a smaller loss than cabin heating. Trip range multiplies full-charge range by the charge window (start % − reserve %).
- Battery
- Usable battery capacity in kWh
- Eff
- Rated consumption in kWh per 100 miles
- S(v)
- Speed factor at cruising speed v (mph), 1.0 at 55 mph
- T
- Temperature penalty as a fraction of range
Worked examples
75 kWh EV at 65 mph on a mild day
At 55 mph the car would cover 75 ÷ 28 × 100 = 268 miles. At 65 mph the speed factor is 1.171, so consumption rises to 32.8 kWh/100 mi and full range falls to about 229 miles. Driving from 90% down to 10% uses 80% of the pack: about 183 miles.
Winter highway trip at 20°F with the heater on
At 70 mph the speed factor is 1.268, giving 211 miles in mild weather. AAA’s 41% cold-weather loss with the heater running cuts that to about 125 miles, and from 100% down to a 10% reserve you have about 112 miles.
Compact EV in town at 35 mph
At 35 mph the speed factor is about 0.76, so the 240-mile rated range stretches. With the heater off at 60°F the penalty is 30% of 11.2%, about 3.4%, leaving roughly 305 miles on a full charge.
Frequently asked questions
How much range does an EV lose in cold weather?+
In AAA’s 2019 test, using the heater at 20°F cut average range by 41% compared with 75°F. Heat pumps, preconditioning while plugged in and using seat heaters instead of cabin heat can reduce the loss considerably.
Why is my EV range lower on the highway?+
Aerodynamic drag rises with the square of speed, so going from 55 to 75 mph raises energy use per mile by roughly a third. Unlike gas cars, EVs do not gain efficiency on the highway because they have no idling or low-gear losses to avoid.
What is the difference between usable and gross battery capacity?+
Manufacturers keep a buffer at the top and bottom of the battery that you cannot use. Usable capacity is typically a few percent below the gross figure, and it is the number that determines range.
Why should I keep a reserve when planning a trip?+
Chargers can be busy or out of service, headwinds and hills raise consumption, and the range estimate is approximate. Arriving with 10–20% left gives you room to reach another charger.
Does hot weather reduce EV range?+
Yes, but less than cold. AAA measured a 17% loss at 95°F with air-conditioning running, largely from the A/C load and battery cooling.