MPGe Explained: Energy Equivalence, Charging Losses and Range
By Convert Calc Editorial Team · Published · Updated
MPGe means miles per gallon of gasoline equivalent. It expresses distance per energy equivalent; ordinary liquid-fuel MPG expresses distance per actual gallon. Ordinary MPG does not use the MPGe energy-equivalence constant.
The energy equivalence
EPA’s testing explanation uses 33.7 kWh as the energy equivalent of a gallon of gasoline. A hypothetical 100 MPGe value represents 100 miles for that energy amount.
Published EPA electric MPGe includes charging losses and accounts for energy at the outlet. It is therefore a different energy boundary from usable battery capacity. The electric-vehicle label guide also explains the consumption value in kWh per 100 miles.
Keep the energy denominator consistent
Dividing a hypothetical 115 MPGe by 33.7 gives approximately 3.41246 miles per outlet kWh under that accounting. Multiplying this by usable battery kWh mixes two different energy quantities and does not derive EPA range.
If both quantities explicitly describe usable battery energy under matching conditions, a hypothetical 75 kWh × 4 miles per battery kWh = 300 miles is dimensionally consistent. This is an assumed battery-energy example, not an EPA range calculation or a vehicle guarantee. EPA range uses a separate test procedure described in its testing source.
A limited energy-cost comparison
For hypothetical constant prices and matching measurement boundaries:
- Liquid fuel cost per mile = price per named gallon / MPG using that gallon.
- Electricity energy cost per mile = price per outlet kWh × 33.7 / MPGe.
These formulas exclude fees and other ownership costs. They do not establish which vehicle is cheaper for an actual trip, and a rating is not a guarantee of consumption under different conditions.
See the fuel pillar for liquid-fuel conversions, MPG and L/100km examples for reciprocal arithmetic and kWh to joules for energy-unit conversion.
Reviewed October 6, 2026 against the linked EPA sources.