How to Read the EPA Fuel Economy Label

Every new car and light truck sold in the US carries a fuel economy and environment label on its window sticker, produced jointly by the Environmental Protection Agency and the Department of Transportation. It packs a lot into a small space, and most buyers read only the big MPG number. The rest of the label answers more useful questions: what the car will cost to run, how it compares with everything else on sale, and how much it pollutes. This explainer goes through it line by line.

City, highway and combined MPG

The largest number is combined MPG, a weighted average that assumes 55% city and 45% highway driving. Beside it are the separate city and highway figures. They come from laboratory tests on a dynamometer, using set driving cycles that include stop-and-go traffic, highway speeds, hard acceleration, air conditioning and cold starts, and EPA adjusts the results to better match what drivers see on the road.

Across the 1,247 gasoline and diesel model years with EPA figures in our index, the median is 22 MPG city, 34 highway and 27 combined. That gives you a reference point: a car rated well above 27 combined is efficient for the market we cover, one well below it is thirsty. Hybrids are the exception to the usual pattern; regenerative braking helps most in traffic, so some hybrids are rated higher in the city than on the highway. In our index, 1 model year is rated that way.

Use the figures to compare cars, not to predict your own mileage exactly. Cold weather, short trips, high speeds, roof racks, heavy loads and under-inflated tires all reduce real-world economy, and the effect is larger on some vehicles than others.

Gallons per 100 miles

Under the MPG figure is a smaller line showing fuel consumed per 100 miles. It is the better number for comparing costs, because MPG is not linear: improving from 10 to 20 MPG saves 5 gallons every 100 miles, while improving from 30 to 40 MPG saves less than one. If you are choosing between two thirsty vehicles, a small MPG gain is worth more money than the same gain between two efficient ones.

Annual fuel cost and five-year savings

The label estimates what the vehicle will cost to fuel each year, assuming 15,000 miles of driving and a fuel price EPA sets for that model year. The median estimate across our gasoline and diesel model years is $2,250a year. Because the assumed price changes from year to year, compare annual cost only between vehicles of the same model year; for older vehicles, recalculate with today’s prices.

A separate box says how much you would save or spendon fuel over five years compared with the average new vehicle. It is a quick way to see whether a car’s efficiency is worth paying more for.

Fuel economy and greenhouse gas rating

A 1-to-10 slider rates the vehicle’s tailpipe carbon dioxide emissions against all new vehicles that year, with 10 the best. The label also states CO₂ in grams per mile. Because CO₂ from burning fuel is directly proportional to how much fuel is burned, this rating tracks fuel economy closely. Electric vehicles score 10 because they have no tailpipe emissions, although generating the electricity does produce emissions that vary by region.

Smog rating

A second 1-to-10 slider rates tailpipe pollutants that cause smog and harm health, such as nitrogen oxides and hydrocarbons, against the emissions standards the vehicle was certified to. It is mostly independent of fuel economy: a large truck can have a good smog rating and a poor greenhouse gas rating. The median in our index is 5 for smog and 5 for greenhouse gas.

Electric and plug-in hybrid labels

Labels for electric vehicles replace MPG with MPGe, miles per gallon equivalent, treating 33.7 kWh of electricity as equal to one gallon of gasoline. More useful for budgeting is kWh per 100 miles, which you can multiply by your electricity price, and the driving range on a full charge, which the label also shows along with charging time. Plug-in hybrid labels show both: the electric-only range and efficiency, and the MPG once the battery is depleted.

EV range is especially sensitive to temperature and speed. Cold weather and sustained highway driving can cut real-world range substantially below the label, which matters more for a used EV whose battery has also aged. Our guide to buying a used electric car covers range and battery checks.

The QR code and fueleconomy.gov

The label carries a QR code linking to fueleconomy.gov, where you can enter your own mileage and fuel price and compare vehicles side by side. That site is the source of the EPA figures on our fuel economy pages and in each vehicle report, so you can always check our numbers against the original.

Sources

• fueleconomy.gov: Learn about the label — EPA and DOT’s own guide to each element
• fueleconomy.gov — the EPA figures behind our fuel economy data