EPA City, Highway and Combined MPG: How to Use the Numbers

• EPA ratings use laboratory tests and adjustments for driving conditions. They give you a common basis for comparison.
• The combined calculation uses fuel consumed per mile. Multiplying the two MPG ratings by their driving shares and adding them gives the wrong average.
• The 2021 Toyota RAV4 Hybrid AWD example is rated 41 city, 38 highway and 40 combined MPG.
• EPA label cost estimates assume 15,000 miles per year and a projected fuel price. Use your own mileage and local price for a budget.

City and highway. The vehicle runs on rollers called a dynamometer while the test follows prescribed driving cycles. The published ratings account for more conditions than a simple city trip and highway trip. They are estimates for the configuration, not a measurement of the used car you are viewing.

Combined. The calculation is 1 / (0.55 / city MPG + 0.45 / highway MPG). This is a weighted harmonic average: calculate the fuel used for each share of the trip, add it, then divide distance by fuel used.

Using the RAV4's rounded ratings gives 1 / (0.55 / 41 + 0.45 / 38), or about 39.59 MPG. That rounds to its published 40 combined MPG. The calculation illustrates the method; rounded city and highway figures will not reproduce every vehicle's official combined rating exactly.

Annual cost. At 40 MPG, driving 15,000 miles uses 375 gallons. Multiply that by the price per gallon to estimate the fuel bill. The table uses the latest national regular-gasoline price CarTold has on file. Check the displayed price date and substitute your local price in the calculator.

For a driving mix that differs from EPA's, estimate city and highway fuel use separately. The calculator does that from the mileage and city-driving share you enter, so its result can differ from a cost based on the rounded combined rating.

1. Match the vehicle. Choose the correct engine, drivetrain and hybrid version before comparing ratings.
2. Set your mileage. Estimate a typical year of commuting and other driving instead of accepting a default.
3. Use the fuel you will buy. Check the car's fuel requirements. In the calculator, enter the local price for Vehicle A and check the displayed price assumption for Vehicle B.
4. Compare annual costs. Use the Fuel Cost Calculator with the same mileage and driving mix for both cars. Try a higher price for Vehicle A to see how its estimate changes; Vehicle B keeps its separate price assumption.

This example covers gasoline vehicles, including hybrids that do not plug in. It does not calculate electric-vehicle MPGe or plug-in-hybrid charging costs. EPA ratings cannot guarantee real-world MPG. The table holds annual mileage constant and uses a national average price; the calculator lets you change those assumptions. Fuel cost is one ownership expense alongside repairs, maintenance, insurance and other costs.

The RAV4 ratings retain the source check from 2026-08-10. EPA's label guide and testing explanation describe the ratings and cost assumptions. Its fuel-economy testing questions and answers specifies the harmonic formula.

The fuel-price date and dollar figures use CarTold's latest stored EIA national regular-gasoline price. The annual-cost calculation is miles divided by MPG, multiplied by price per gallon. It estimates a fuel bill using the displayed assumptions.

• Fuel Cost Calculator
• Data sources
• How CarTold's reports work