EV Range & Efficiency Calculator
This calculator converts your EV's battery capacity, vehicle efficiency, and usable-capacity buffer into an EPA-rated range estimate, then applies a driving-condition derate to show what range you can realistically expect on the road. The gap between EPA-rated and real-world range is driven almost entirely by speed and temperature, not battery defects, so understanding it is one of the most useful things an EV buyer or owner can do. For how that range fades over years of ownership, see our EV Battery Life Calculator, and for the per-mile and per-charge economics of running an EV, see our EV Charging Cost Calculator.
Total (gross) battery pack capacity as listed by the manufacturer.
Typical modern EVs achieve 2.8-4.0 miles/kWh depending on vehicle size and aerodynamics. 3.3 mi/kWh is roughly equivalent to 30 kWh per 100 miles.
Automakers typically reserve a small buffer of total capacity (unusable to the driver) to protect battery longevity.
Auto-filled by your driving conditions selection above, but still editable if you want a custom derate.
battery capacity × (usable % ÷ 100)
usable battery capacity × vehicle efficiency
EPA-rated range × (1 − derate ÷ 100) — 15% derate applied
Results update live as you type. For planning and field-check estimates — always verify against applicable standards and equipment ratings.
How we calculate this →The gap between EPA-rated range and real-world range is one of the most common sources of EV owner frustration -- and it's driven almost entirely by speed and temperature, not battery defects. Highway driving at 70+ mph can cut range by roughly 15% due to aerodynamic drag increasing sharply with speed, while cold weather below freezing can cut another 15-20% from reduced battery chemistry efficiency and cabin heating draw. Combined, a 235-mile EPA-rated EV can realistically deliver closer to 165-200 miles on a cold highway trip.
How EV range and efficiency are calculated
This calculator works in three steps that mirror how an EV actually turns battery capacity into driving distance. Usable Battery Capacity (kWh) = Battery Capacity (kWh) × (Usable Battery Percentage (%) ÷ 100). Automakers reserve a small buffer at both the top and bottom of the charge range to protect long-term battery health, so the driver never sees the full gross capacity; at 75 kWh gross and 95% usable, that leaves 71.25 kWh of drivable energy.
EPA-Rated Range (miles) = Usable Battery Capacity (kWh) × Vehicle Efficiency (miles per kWh). Vehicle efficiency is the distance the EV travels per kWh of energy consumed, and it is the single most important factor in how far a given battery pack will take you; at 71.25 kWh and 3.3 mi/kWh, that is about 235 miles, which matches how the EPA derives its range ratings from the FTP-75 and HWFET test cycles.
Real-World Estimated Range (miles) = EPA-Rated Range (miles) × (1 − Driving Condition Derate (%) ÷ 100). The derate captures how much real-world conditions shrink range below the EPA figure: highway speeds above 70 mph cut roughly 15% from aerodynamic drag (which rises roughly with the square of speed), cold weather below freezing cuts roughly 20% from reduced battery chemistry efficiency and cabin heating draw, and the two combined can cut 30%. At 235 miles EPA-rated with a 15% highway derate, real-world range is about 200 miles. The derate field auto-fills from the driving-conditions dropdown but stays editable, so you can model any custom penalty. Data sources: EPA vehicle efficiency testing procedures (FTP-75 and HWFET cycles); EV manufacturer efficiency specifications; real-world EV range studies from Geotab, AAA, and independent testing; aerodynamic drag and cold-weather penalty research from NREL and DOE.