E85 vs. Gasoline: Cost, Fuel Economy, and Which One Saves You Money

You’ve seen E85 at the pump, often priced significantly lower than regular gasoline. But does cheaper per gallon mean cheaper per mile? Understanding the true cost of E85 versus gasoline requires looking beyond the price on the pump and calculating the real-world economics. Let’s break down everything you need to know about E85 fuel economy and whether it will actually save you money.

The Fuel Economy Reality: Why E85 Gets Fewer Miles Per Gallon

Here’s the fundamental truth about E85: you will get fewer miles per gallon compared to gasoline. This isn’t a defect or problem with E85—it’s simple chemistry.

The Energy Content Difference

E85 contains approximately 75% of gasoline’s energy per gallon, with E85 having 83,950–95,450 BTUs compared to gasoline’s 114,000–120,000 BTUs. Because ethanol has lower energy density than gasoline, your engine needs to burn more fuel to produce the same amount of power.

Due to ethanol’s lower energy content, flex fuel vehicles typically experience a 15% to 27% decrease in miles per gallon when using E85 compared to regular gasoline. The actual decrease depends on several factors:

• **The ethanol content**: E85 can range from 51% to 83% ethanol, with higher ethanol percentages resulting in lower fuel economy
• **Your vehicle**: Smaller, newer vehicles may see only a 10-15% decrease, while larger vehicles typically see 15-27% reduction
• **Driving conditions**: Highway driving typically shows better relative performance than city driving
• **Engine optimization**: Vehicles specifically tuned for E85 can minimize fuel economy losses

Real-World Fuel Economy Examples

In testing, a 2007 Chevrolet Tahoe averaged 18.3 MPG on gasoline but only 13.5 MPG on E85—a 26.5% decrease in fuel economy. A 2014 Ford Focus gets 40 MPG highway on gasoline but only 28 MPG with E85, representing a 30% reduction.

However, the MPG decrease varies significantly by vehicle and conditions:

• **Small vehicles and hybrids**: 10-15% MPG reduction
• **Mid-size vehicles**: 15-20% MPG reduction
• **Large trucks and SUVs**: 20-27% MPG reduction
• **Performance vehicles (tuned for E85)**: 15-20% MPG reduction

Driving style also affects the differential. Steady highway driving tends to generate smaller MPG losses (10-20% lower than gasoline) while aggressive city driving with frequent acceleration can result in 20-30% lower MPG.

The True Cost Comparison: Cost Per Mile, Not Cost Per Gallon

When comparing E85 to gasoline, forget about miles per gallon for a moment. What really matters is cost per mile—how much you’re spending to drive a given distance.

The Math That Matters

Let’s use a real-world example to illustrate why cost per mile is critical:

Scenario: You own a vehicle that gets 25 MPG on regular gasoline

• **Gasoline**: $3.50/gallon
• **E85**: $2.50/gallon (about $1 less per gallon)

On Gasoline:

• 25 MPG means each gallon takes you 25 miles
• At $3.50/gallon, you’re paying $0.14 per mile
• To drive 15,000 miles/year costs $2,100

On E85 (assuming 20% MPG decrease):

• 20 MPG (down from 25 MPG on gas)
• At $2.50/gallon, you’re paying $0.125 per mile
• To drive 15,000 miles/year costs $1,875

Savings: $225 per year

The Breakeven Formula

To determine if E85 saves money, calculate your cost per mile for both fuels. It costs 20 cents per mile to drive on gasoline but only 14-16 cents per mile on E85 in certain pricing scenarios, representing a 20-30% decrease in fueling costs.

Here’s the critical calculation: E85 needs to be at least 15-20% cheaper per gallon than gasoline to break even on cost, given the typical fuel economy decrease. If the price difference is greater, you save money. If it’s less, you’re spending more despite the lower pump price.

When E85 Actually Saves You Money

E85 provides genuine savings when the price difference is substantial:

In scenarios where gasoline is $5.00/gallon and E85 is $3.25/gallon, spending $30 on gas provides 150 miles of range (20 cents/mile), while $30 on E85 provides 184-207 miles (14-16 cents/mile).

Over 20,000 miles annually, this price differential can save $800-$1,200 per year. However, these savings depend entirely on maintaining a significant price gap between E85 and gasoline in your area.

Regional Price Variations

E85 prices vary dramatically by location:

• **Midwest (Corn Belt states)**: E85 is often $0.80-$1.50 cheaper per gallon than regular gasoline
• **Coastal states**: E85 may only be $0.30-$0.50 cheaper, making it less economical
• **National average** (current): E85 typically runs $0.50-$0.70 less per gallon than regular gas

The key is checking prices in your specific area. Use E85GasFinder.com or E85Prices.com to find current prices near you.

Beyond the Math: Other Cost Considerations

Maintenance Costs

Some performance enthusiasts report that E85 can impact maintenance intervals:

• Oil may need to be changed more frequently (though this is debated)
• Fuel filters may require more frequent replacement
• Fuel injectors need monitoring for potential clogging

However, E85’s cleaning properties can actually benefit your fuel system by reducing carbon deposits over time, potentially improving long-term efficiency.

Reduced Driving Range

A Chevrolet Tahoe’s driving range decreased to about 300 miles on a full tank of E85 compared with about 440 miles on gasoline. This means more frequent fill-ups, which adds inconvenience even if you’re saving money.

Limited Availability

With only about 3,900 E85 stations nationwide (concentrated in the Midwest), you may need to go out of your way to find E85. This extra driving can offset some savings.

Performance Benefits Worth Considering

While we’re focused on costs, E85 offers performance advantages that have value for some drivers:

Higher Octane Rating

E85 typically has an octane rating of 100-105, compared to 87 for regular gas or 91-93 for premium. For vehicles that require premium gasoline, the cost comparison changes significantly:

If your car requires premium gasoline:

• Premium gas: $4.00/gallon
• E85: $2.50/gallon
• The larger price gap makes E85 much more economical

Increased Power Output

E85’s higher octane enables advanced ignition timing and cleaner combustion, while ethanol’s cooling effect increases air density in cylinders for better efficiency. Many performance vehicles see 5-15% power gains on E85, especially turbocharged applications.

The Bottom Line: Does E85 Save Money?

Whether E85 saves you money depends on four factors:

• **Price differential in your area**: You need at least $0.50-$0.75/gallon savings for E85 to be economical for most vehicles
• **Your vehicle’s MPG decrease**: Smaller decreases (10-15%) make E85 more viable than larger ones (25-30%)
• **Your annual mileage**: Higher mileage amplifies savings (or losses)
• **E85 availability**: Convenience matters—driving far to save money defeats the purpose

Use This Quick Decision Rule:

Calculate your breakeven price:

• Find your vehicle’s gas MPG and E85 MPG (usually 15-25% lower)
• Multiply the gasoline price by: (E85 MPG ÷ Gas MPG)
• If E85 is cheaper than this calculated price, you save money

Example:

• Your car gets 30 MPG gas, 24 MPG E85
• Gas is $3.60/gallon
• Breakeven E85 price: $3.60 × (24÷30) = $2.88
• If E85 is less than $2.88, you save money

Tips for Maximizing E85 Savings

If you decide to use E85:

• **Check prices frequently**: E85 prices fluctuate more than gasoline
• **Track your actual MPG**: Use a fuel economy app to know your real-world numbers
• **Consider blending**: Mix E85 with regular gas to balance cost and range
• **Drive efficiently**: Smooth acceleration and steady speeds minimize the MPG penalty
• **Monitor availability**: Plan trips around E85 station locations

The Environmental Factor

While we’ve focused on economics, remember that E85 offers environmental benefits:

• Reduced greenhouse gas emissions
• Support for domestic agriculture
• Decreased dependence on foreign oil

For some drivers, these benefits justify using E85 even if the pure financial savings are modest.

Final Verdict

E85 can save you money, but it’s not automatic. In the Midwest with a price gap of $1+ per gallon, savings are substantial. In coastal areas with only $0.30-$0.50 price differences, you may actually spend more despite the lower pump price.

Best candidates for E85 savings:

• High-mileage drivers in the Midwest
• Owners of vehicles requiring premium gasoline
• Those with vehicles showing only 10-15% MPG decrease
• Performance enthusiasts who value the power benefits

Stick with gasoline if:

• E85 is less than $0.50/gallon cheaper in your area
• Your vehicle shows 25%+ MPG decrease on E85
• E85 stations are inconveniently located
• You prioritize maximum driving range

The only way to know for certain is to calculate based on your specific vehicle, driving patterns, and local fuel prices. Use online calculators or track a few tanks yourself to determine whether E85 truly saves you money.