E85 is a fuel blend containing 51-83% ethanol and 17-49% gasoline (the percentage varies seasonally and by region). It's designed for flex-fuel vehicles (FFVs) that can run on any blend of gasoline and ethanol. E85 typically has an octane rating of 100-105, higher than regular gasoline (87), which can improve performance in compatible engines.

Is E85 cheaper than regular gasoline?

E85 is usually priced lower per gallon than regular gasoline, often 20-30% less. However, E85 contains less energy per gallon than gasoline (about 27% less energy content), meaning you'll get fewer miles per gallon. To determine if E85 is actually cheaper, you must calculate cost per mile, not just cost per gallon. E85 may save money only when it's significantly cheaper than gas.

How much does E85 reduce fuel economy?

E85 typically reduces fuel economy by approximately 15-30% compared to regular gasoline, with 20-27% being most common. This is because ethanol has lower energy content (about 76,000 BTU/gallon) compared to gasoline (about 115,000 BTU/gallon). A vehicle getting 30 mpg on gasoline might get 22-25 mpg on E85. Actual reduction varies by vehicle, driving conditions, and E85 ethanol percentage.

Can I use E85 in any vehicle?

No, E85 should only be used in flex-fuel vehicles (FFVs) specifically designed for it. FFVs have modified fuel systems including compatible fuel lines, sensors, and engine management programming. Using E85 in a non-FFV can damage fuel system components, cause poor performance, and void warranties. Check your owner's manual or look for a flex-fuel badge/yellow gas cap to confirm your vehicle's compatibility.

What are the environmental benefits of E85?

E85 can reduce greenhouse gas emissions by approximately 15-45% compared to gasoline, depending on how the ethanol is produced. Ethanol is renewable and domestically produced (mainly from corn in the US), reducing dependence on foreign oil. However, the net environmental benefit is debated due to land use for corn production, fertilizer use, and energy required for ethanol production and transportation.

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E85 Fuel Calculator

Compare costs and calculate blends for E85 vs Regular gasoline.

Fuel Prices & Specs

Regular Gas Price ($)

E85 Price ($)

MPG (on Gas)

Tank Size (Gallons)

How to Use This Calculator

Enter Current Fuel Prices

Input the current price per gallon for both E85 and regular gasoline at your local stations. These prices can vary significantly by location and season, so use current local prices for accurate cost comparisons.

Enter Your Vehicle's Fuel Economy

Input your vehicle's fuel economy in miles per gallon (MPG) for both regular gasoline and E85 if known. If you don't know your E85 MPG, the calculator can estimate it - E85 typically gives 20-27% lower MPG than gasoline. Use your actual observed fuel economy for most accurate results.

Calculate Cost Comparison

The calculator will determine the cost per mile for each fuel type and show which is actually cheaper to operate. Even though E85 has a lower price per gallon, it may not save money due to reduced fuel economy. The calculator shows the break-even price where both fuels cost the same per mile.

Optional: Calculate Custom Blends

If you want to mix E85 with regular gasoline for a custom ethanol percentage, enter your desired blend ratio. The calculator will show the resulting ethanol content and effective octane rating. Some FFV owners blend fuels for optimal cost/performance balance.