MPGe & Efficiency Converter
Convert between mi/kWh, kWh per 100 miles, and MPGe — the three units used to describe EV efficiency.
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Three ways to describe the same thing
EV efficiency is reported in three different units, depending on who is doing the reporting:
- mi/kWh — miles driven per kilowatt-hour of energy. Higher is better. Loved by car nerds and trip planners.
- kWh per 100 miles — how much energy you use to drive 100 miles. Lower is better. Used on EPA window stickers (similar to L/100km in Europe).
- MPGe — “miles per gallon equivalent.” The EPA defines 1 gallon of gasoline as 33.7 kWh of energy, so MPGe = mi/kWh × 33.7. Higher is better.
The conversion formulas
Worked example
An EV that gets 3.5 mi/kWh uses 100 ÷ 3.5 = 28.6 kWh per 100 miles, which is 3.5 × 33.7 = 118 MPGe.
Reference points
- Most efficient new EVs: 4.0–5.0 mi/kWh (130–170 MPGe)
- Typical mid-size EVs: 3.0–4.0 mi/kWh (100–135 MPGe)
- Performance EVs & SUVs: 2.5–3.0 mi/kWh (85–100 MPGe)
- EV trucks & big-battery cars: 2.0–2.5 mi/kWh (65–85 MPGe)
- A typical gas car: ~25–30 MPG — an EV is usually 3–5× more energy-efficient
Frequently asked
Why does MPGe exist?
The EPA needs a single number that lets buyers compare an EV to a gas car. MPGe converts the EV's energy use into the gas-equivalent: 1 gallon of gasoline contains roughly 33.7 kWh of energy, so an EV that uses 1 kWh per 33.7 miles would be 1 MPGe.
What is a good MPGe?
Most modern EVs score 100–135 MPGe combined. Compact-efficient EVs (Hyundai Ioniq 6, Tesla Model 3 RWD) get 130+ MPGe. Mid-size SUVs run 100–120 MPGe. Performance EVs and trucks land 80–100 MPGe.
How does MPGe compare to gas-car MPG?
A 132 MPGe EV is roughly 4–5× more energy-efficient than a 28 MPG gas car. That said, this is energy efficiency — not cost efficiency. Cost depends on electricity vs gas prices, which are typically tilted strongly in the EV's favor.
Why is MPGe = mi/kWh × 33.7?
The EPA defines 1 gallon of gasoline as containing 33.7 kWh of energy. So if an EV travels 3.5 miles per kWh, it would travel 3.5 × 33.7 = 118 miles on the energy equivalent of one gallon of gas — hence 118 MPGe.
Which unit should I use for day-to-day trip planning?
mi/kWh — it is by far the most intuitive. Battery kWh × mi/kWh = range. Daily miles ÷ mi/kWh = daily kWh use. Electricity rate ÷ mi/kWh = cost per mile. Memorize your car's mi/kWh and most other math falls out cleanly.
Why 33.7 kWh equals 1 gallon of gasoline (MPGe)
The U.S. EPA defines 1 gallon of gasoline equivalent as containing 33.7 kilowatt-hours (kWh) of chemical energy. That fixed conversion factor lets drivers compare an EV's electricity consumption directly against traditional MPG ratings:
- 3.0 mi/kWh: 33.3 kWh per 100 miles ≈ 101.1 MPGe (typical for larger electric SUVs and pickups at highway speed).
- 3.5 mi/kWh: 28.6 kWh per 100 miles ≈ 118.0 MPGe (common compact/mid-size crossover blended average).
- 4.0 mi/kWh: 25.0 kWh per 100 miles ≈ 134.8 MPGe (aerodynamic sedans in mild city and suburban driving).
Window sticker vs. dashboard readout: EPA combined kWh / 100 mi and MPGe label numbers include typical AC charging losses from the wall outlet, whereas most EV trip computers report battery-to-wheels efficiency only. For utility budgeting, check your home electricity cost using our EV Charging Cost Calculator and read EV efficiency explained.