EV Efficiency / Mileage Calculator
Enter the distance you drove and the energy consumed (from your EV's trip meter) to calculate your efficiency in any unit.
Reviewed by the ToolNestr Editorial Team — July 2026
Efficiency comparison across EV classes
The bars below show the typical efficiency range for different EV classes under mixed conditions.
EV Owner Tracking Efficiency
Monitor your efficiency over time to understand how driving habits, seasonal changes, and tire pressure affect your car's real-world energy consumption.
Fleet Manager
Track efficiency metrics across your EV fleet to identify which drivers and routes achieve the best energy economy and where coaching can improve results.
Buyer Comparing Models
Compare EPA efficiency ratings of different EV models side by side to find the vehicle that delivers the lowest energy cost per mile for your driving patterns.
Driving Coach
Use efficiency data to help EV owners improve their driving technique — smoother acceleration, earlier regen, and optimal speed for maximum range.
| Model | EPA mi/kWh | EPA Wh/mi | EPA MPGe | Battery (kWh) | EPA range (mi) |
|---|---|---|---|---|---|
| Hyundai Ioniq 6 RWD | 4.7 | 213 | 158 | 77 | 361 |
| Tesla Model 3 RWD | 4.5 | 222 | 152 | 60 | 272 |
| Tesla Model Y AWD | 3.8 | 263 | 128 | 81 | 330 |
| Chevrolet Bolt EV | 4.0 | 250 | 135 | 65 | 259 |
| Kia EV6 RWD | 4.0 | 250 | 135 | 77 | 310 |
| Ford Mustang Mach-E AWD | 3.2 | 313 | 108 | 91 | 270 |
| Volkswagen ID.4 Pro | 3.4 | 294 | 114 | 82 | 275 |
| BMW i4 eDrive40 | 3.8 | 263 | 128 | 83 | 301 |
How to use the EV Efficiency Calculator
Record trip distance
Use your EV's trip odometer to record the distance driven since your last charge or over a specific trip. Enter it in miles or kilometres.
Note energy used
Check your EV's energy display or trip computer for the kWh consumed during the same trip. Input this along with your battery capacity for range estimation.
Get efficiency metrics
See your efficiency in mi/kWh, Wh/mi, km/kWh, kWh/100km, plus your cost per mile and estimated full-battery range.
Tips for improving EV efficiency
Efficiency drops at high speed
Aerodynamic drag increases with the square of speed. Driving at 120 km/h (75 mph) uses about 20–30% more energy than driving at 90 km/h (56 mph). On highways, set cruise control to the speed limit and avoid unnecessary acceleration.
Climate control impact
Heating the cabin in winter draws 3–5 kW — equivalent to adding a 10–20% load. Air conditioning in summer draws 1–2 kW. Precondition while plugged in, use seat heaters (far more efficient), and set the cabin temp to 20°C (68°F) rather than 25°C (77°F).
Regen driving helps
Maximise regenerative braking by using one-pedal driving mode and anticipating stops. Smooth deceleration captures more energy than hard braking. In city driving, good regen technique can recover 15–25% of acceleration energy, boosting overall efficiency by 10–15%.
What is mi/kWh?
Miles per kilowatt-hour (mi/kWh) is the primary efficiency metric for EVs. It tells you how far you can travel on one kilowatt-hour of battery energy. Most modern EVs achieve between 3.0 and 4.5 mi/kWh under normal conditions. To put it in perspective: at 4.0 mi/kWh, a 75 kWh battery delivers 300 miles of range. At 3.0 mi/kWh, the same battery gives only 225 miles — a 25% difference purely from efficiency.
How EV efficiency is calculated
EV efficiency is the distance travelled per unit of energy consumed: efficiency = distance / energy used. In imperial units this is miles per kilowatt-hour (mi/kWh).
The inverse — energy consumed per distance — is expressed as Wh/mi or kWh/100km. Both metrics describe the same relationship and can be converted between each other.
Worked example
How mi/kWh compares to MPG
The EPA created MPGe (miles per gallon equivalent) to help consumers compare EVs to gas cars. One gallon of gasoline contains about 33.7 kWh of energy. So an EV that achieves 3.5 mi/kWh is equivalent to a gas car getting 118 MPG (33.7 × 3.5). Even the most efficient gas hybrids struggle to reach 50–60 MPG, meaning EVs are typically 2–3x more energy efficient than their gasoline counterparts.
Factors affecting EV efficiency
Speed is the biggest factor — every 10 km/h above 90 km/h reduces efficiency by 5–8%. Temperature is second: batteries are less efficient in cold and heat. Driving style matters significantly: smooth driving with anticipation can improve efficiency by 15–20% compared to aggressive driving. Tire condition (pressure, tread, rolling resistance), payload weight, and wind direction all play measurable roles in efficiency variation.
Seasonal variation in EV efficiency
Spring and fall offer the best efficiency (often exceeding EPA ratings by 5–10%) because moderate temperatures eliminate the need for cabin HVAC and the battery operates at its ideal temperature. Summer sees a 5–10% drop from AC usage. Winter is the worst season with 15–30% drops from battery cold inertia and cabin heating. Altitude also plays a role: EVs are slightly more efficient at sea level than at high altitudes due to thinner air reducing drag.
Frequently asked questions
What is mi/kWh?
Miles per kilowatt-hour (mi/kWh) is the EV equivalent of MPG. It measures how many miles you can travel on 1 kWh of battery energy. Most EVs achieve 3–4 mi/kWh in mixed driving. Higher is better — 4 mi/kWh means you use less energy per mile than 3 mi/kWh.
How does mi/kWh compare to MPG?
1 mi/kWh is roughly equivalent to 33.7 MPGe (miles per gallon equivalent). A modern EV getting 3.5 mi/kWh achieves about 118 MPGe — far better than even the most efficient gas car. The EPA uses MPGe to help consumers compare across fuel types.
What is a good EV efficiency number?
For a modern EV: 4.0+ mi/kWh (6.4+ km/kWh) is excellent, 3.5–4.0 mi/kWh (5.6–6.4 km/kWh) is good, 3.0–3.5 mi/kWh (4.8–5.6 km/kWh) is average for an SUV or crossover, and below 3.0 mi/kWh (4.8 km/kWh) is poor — often seen in cold weather or high-speed driving.
How do I calculate my EV efficiency?
Reset your trip odometer at a full charge, drive normally, then note the miles driven and kWh consumed from your EV's trip meter or energy display. Divide miles by kWh (mi/kWh) or divide kWh by miles × 1000 (Wh/mi). This calculator does it instantly.
Why does my efficiency vary so much?
EV efficiency is highly sensitive to driving conditions. Speed (aerodynamic drag increases with velocity squared), temperature (battery chemistry + HVAC), terrain (hills cost energy), driving style (aggressive vs smooth), tire pressure, and even wind all cause significant variation day to day.
Does regenerative braking improve efficiency?
Yes. One-pedal driving with strong regen captures energy that would otherwise be lost as heat in friction brakes. Regen can recover 15–25% of the energy used during acceleration, especially in city driving with frequent stops. Highway driving sees less benefit from regen.
How does winter affect EV efficiency?
Winter is the biggest efficiency killer. Cold batteries have higher internal resistance, and cabin heating draws 3–5 kW. Expect a 15–30% drop in mi/kWh in winter vs spring/fall. Preconditioning while plugged in and using seat heaters instead of cabin air can reduce the impact.
How do I see my real-time efficiency?
Most EVs display current efficiency on the instrument cluster or energy app. Some show a live bar chart or numeric readout. Use the "since last charge" or "trip" display to get an average over a longer distance rather than the instantaneous reading.
What is Wh/mi?
Watt-hours per mile (Wh/mi) is the inverse of mi/kWh — it measures energy consumed per mile. Lower is better. A typical EV uses 250–300 Wh/mi in mixed driving. Multiply by 1,000 to convert kWh consumed: 275 Wh/mi means 0.275 kWh per mile or 3.64 mi/kWh.
Can I use efficiency numbers to compare EVs?
Yes, but compare numbers measured under the same conditions. EPA ratings are standardized. Real-world efficiency varies, so use EPA numbers for model-to-model comparisons and real-world numbers to track how your driving habits affect your specific car.
Sources & references
This tool uses standard formulas and reference values from:
- • SAE International standards (e.g. J1349 engine power, J1634 EV range). sae.org
- • U.S. DOE / EPA — fueleconomy.gov, official efficiency, MPGe and charging figures. fueleconomy.gov
- • Vehicle manufacturer service specifications — always defer to the OEM figures for your specific vehicle.
General estimates. Follow your manufacturer’s published specifications and a qualified mechanic for safety-critical work.