MPGe Converter
Convert between the EPA's MPGe metric and actual energy consumption.
What this calculator does
Convert between MPGe and kWh per 100 miles using the EPA energy equivalence of 33.7 kWh per gallon of gasoline. The tool also shows kWh per mile so you can use the result for cost or range planning.
Inputs explained
- Mode: Choose whether you are converting to MPGe or from MPGe.
- Input value: Enter MPGe or kWh/100mi based on the selected mode.
How it works / Method
- Use the EPA energy equivalence of 33.7 kWh per gallon.
- Convert MPGe to kWh/100mi or invert the formula to get MPGe.
- Calculate kWh per mile for quick cost math.
Formula(s) used
MPGe = (33.7 * 100) / (kWh/100mi)
kWh/100mi = (33.7 * 100) / MPGe
kWh/mi = (kWh/100mi) / 100
Units: MPGe is miles per gallon equivalent, kWh/100mi is energy per 100 miles.
Input
Results
MPGe
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Approx kWh/100mi
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kWh per mile
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Step-by-step example
Example input: 120 MPGe.
- kWh/100mi: 3370 / 120 = 28.08 kWh/100mi.
- kWh/mi: 28.08 / 100 = 0.281 kWh/mi.
- Inverse check: 3370 / 28.08 = 120 MPGe.
Use cases
- Compare EPA MPGe ratings with energy-per-distance units.
- Convert MPGe to kWh/100mi for cost estimates.
- Translate kWh/100mi values into MPGe for comparisons.
- Standardize efficiency data in spreadsheets.
- Compare EV efficiency to gasoline vehicles on a common basis.
- Feed kWh/mi into range or trip calculators.
Assumptions & limitations
- Uses the EPA constant of 33.7 kWh per gallon equivalent.
- Does not adjust for charging losses or regional test cycles.
- MPGe is a standardized rating, not a guarantee of real world driving.
- Rounding may create small differences in displayed values.
- Does not estimate cost or range by itself.
- Results are for comparison and planning.
Disclaimer: Results are estimates for planning only. Real world energy use varies by conditions and driving style.
Frequently Asked Questions
MPGe stands for 'miles per gallon equivalent.' It's a label number invented by the EPA to let buyers compare EV efficiency to gasoline cars on familiar terms. The conversion benchmark — 33.7 kWh of electricity contains about the same amount of energy as one US gallon of gasoline. So a car rated 120 MPGe uses electricity at the same energy rate as a gas car would burn gasoline at 120 MPG. It's useful for showroom comparison but not so much for daily ownership math, since your electricity bill is in kWh, not gallons.
Divide 3370 by MPGe. So 100 MPGe = 3370 ÷ 100 = 33.7 kWh per 100 miles. A 120 MPGe car works out to 28.1 kWh per 100 miles. The number 3370 comes from 33.7 kWh per gallon-equivalent times 100. This conversion is incredibly useful because kWh per 100 miles ties directly to your electricity bill — multiply it by your tariff and you instantly know cost per 100 miles. MPGe alone doesn't tell you what charging costs; converting to kWh/100 mi closes that loop. Memorize 3370 ÷ MPGe — it's one of the most useful EV math shortcuts.
The official MPGe label generally reflects the EPA's test cycle measurements, which can include some charger losses depending on test methodology, but it's not a perfect representation of what your home meter will show. For real billing purposes, what matters is grid-side energy — what your meter measured — not just what reached the battery. If you want to know your true wall-to-wheel cost, use your charger logs or smart meter data and ignore MPGe for that calculation. MPGe is great for comparing cars, less great for predicting your actual electricity bill.
Because your electricity bill is in kWh, not gallons. With kWh per 100 miles, you just multiply by your tariff and you've got cost per 100 miles done. With MPGe, you have to convert first — divide 3370 by MPGe to get kWh per 100 miles, then multiply by tariff. Two steps versus one. MPGe is built to compare against gasoline MPG numbers, not to calculate your power bill. For showroom comparison, MPGe is fine. For 'what will it cost me to drive this thing 1000 miles a month?' — kWh per 100 miles wins every time.
MPGe and MPG measure different things wearing similar clothes. MPG measures gasoline use directly. MPGe measures electrical energy use scaled to a 'gasoline equivalent' through the 33.7 kWh per gallon ratio. So a 120 MPGe EV doesn't drive 120 miles on a literal gallon of fuel — it uses electricity equivalent to that energy. The fairer comparison is cost per mile. Calculate EV cost per mile from kWh × tariff, gas cost per mile from gas price ÷ MPG, and compare those rupees-per-mile numbers directly. Energy parity and cost parity are very different things in real life.
Two-step process. First, divide 3370 by 120 to get kWh per 100 miles — that's 28.08 kWh/100 mi. Then divide by 100 to scale down to per-mile — 0.281 kWh per mile. So a 120 MPGe EV uses about 0.28 kWh of grid-equivalent energy for every mile. At ■8 per kWh, that's about ■2.25 per mile in fuel cost. The shortcut formula combines both steps: kWh per mile = 33.7 ÷ MPGe. So 33.7 ÷ 120 = 0.281 kWh/mile. Same answer, fewer keystrokes. Worth memorizing if you compare EVs often.
Your dashboard shows what you're actually getting based on real driving — speed, terrain, weather, AC use, you name it. MPGe is a standardized lab measurement designed to compare cars on a level playing field, not to predict your specific commute. So an EV rated 120 MPGe might show 95 MPGe on your dashboard if you drive fast, in winter, or with the heater cranked. Or 135 MPGe if you cruise gently in mild weather. Both are correct in their own context. Use MPGe for comparison shopping; use the dashboard reading to track your actual habits.
Higher MPGe means better efficiency, but range is also about how big the battery is. A small efficient EV with a 40 kWh battery might do 4 miles per kWh — that's 160 miles total. A bigger, less efficient EV with an 80 kWh pack at 3 miles per kWh covers 240 miles despite worse efficiency. So MPGe alone doesn't determine range. The full equation is: range = battery capacity × efficiency. Both matter. When comparing two EVs, look at MPGe and battery size together, not just one number. A long-range EV needs decent efficiency and a meaningful battery.
Convert MPGe to kWh per mile first using the shortcut: 33.7 ÷ MPGe. So a 110 MPGe EV uses 0.306 kWh/mile. Multiply by trip distance to get total energy needed. A 250-mile trip in that car needs about 77 kWh. Then layer in your buffers — 10-15% for highway speed, more for cold weather, plus a charging-loss factor for the wall-side cost. Multiply by your electricity rate to get the trip's fuel cost. MPGe by itself doesn't give you actionable trip numbers; converting to kWh per mile turns it into a planning tool. Don't skip the conversion.
It's an energy-equivalent benchmark — the EPA decided that 33.7 kWh of electricity contains the same amount of usable energy as one US gallon of gasoline. They use it to convert between gas-vehicle MPG and EV MPGe so consumers can compare both on the same window sticker. Note this is energy equivalence, not cost equivalence. 33.7 kWh at ■8 costs ■270, while a gallon of petrol at ■105 per litre is about ■400. So the energy is the same, the dollar cost is wildly different — and that gap is exactly why EVs cost less per mile to fuel.
Sources & references
- U.S. EPA: Fuel economy and EV range testing - Defines MPGe and the 33.7 kWh per gallon equivalent.
- U.S. DOE: MPGe fact of the week - Explains MPGe as an energy equivalence.
- U.S. Energy Information Administration: Measuring electricity - Defines kW and kWh units used in MPGe math.
- Schema.org: FAQPage, WebPage, and BreadcrumbList - Structured data definitions used on this page.