EV Efficiency Metrics: MPGe, kWh/100 Miles, Range, and Cost

What We Know (Sourced)

EPA explains that MPG equivalent (MPGe) is used for plug-in electric vehicles (PEVs) and that it conveys energy consumption using the equivalent energy content of a gallon of gasoline. EPA also provides an example equivalence: 33.7 kilowatt-hours of electricity is used as the energy-equivalent amount to a gallon of gasoline in MPGe examples. Source: U.S. EPA — Fuel Economy and EV Range Testing.

EPA’s electric vehicle label documentation explains that kilowatt-hours per 100 miles tells you how many kilowatt-hours the vehicle would use to travel 100 miles, and it notes that this relates directly to energy used and therefore to cost. Source: U.S. EPA — Text version of the electric vehicle label.

EPA notes that official MPGe values include charging losses so the metric better represents energy use at the outlet. Source: EPA testing documentation.

EPA’s gasoline label documentation also explains why MPGe appears for vehicles that do not use liquid fuels: it enables comparisons across fuels on a standardized basis. Source: U.S. EPA — Text version of the gasoline label.

If you want to see the EV label components laid out visually, EPA provides both an interactive EV label and a text version.

Metric Cheat Sheet

If you want focused explainers for the first two rows, start with: What is MPGe? and kWh per 100 miles explained.

How to Translate Metrics into Cost

Cost comparisons only work when you use the same unit on both sides. Two simple approaches:

• Cost per mile (best for commute and trip budgeting)
• Cost per 100 miles (best for comparing vehicles side-by-side)

Once you have dollars per mile for both, you can compare directly. Full guide: gas vs electric cost per mile.

Common Comparison Mistakes

1) Treating MPGe as a cost metric

MPGe is a standardized energy-equivalence metric, not a guarantee of cost savings. Your cost depends on your electricity prices and where/how you charge.

2) Ignoring charging losses

EPA notes that MPGe values include charging losses to better represent energy use at the outlet. That means “battery-only” numbers can look better than what you pay for.

3) Confusing efficiency with range

Two EVs can have similar kWh/100 miles but very different range because they have different battery sizes. That’s why the label includes both.

4) Forgetting weather and HVAC

Real-world energy use can vary with speed and temperature. If you want a source-based cold-weather baseline, see: fuel economy in cold weather.

What’s Next (Practical Steps)

• Pick the metric that matches your goal: kWh/100 miles for cost, range for convenience, MPGe for cross-fuel comparisons.
• Use official label data as your baseline: compare vehicles consistently before adjusting for your driving.
• Personalize with your own prices: home electricity rate vs public charging matters.
• Track your real results: real-world consumption often varies by route, speed, and weather.

If you want a guided walk-through of label components (MPGe, kWh/100 miles, range), start here: EPA EV label explained.

Why It Matters

EV label metrics exist to make comparisons consistent across vehicles and fuels. EPA’s documentation makes clear that MPGe is an energy-equivalence measure, kWh/100 miles is direct electricity use (and links closely to cost), and official values account for charging losses. Sources: EPA testing and EPA EV label text.

Frequently Asked Questions