Is E85 actually cheaper than gas?

E85 almost always has a lower sticker price than regular gasoline — commonly 15–30% cheaper per gallon. But the price per gallon is only half the equation. Ethanol carries about 27% less energy per gallon than gasoline, so your fuel economy drops on E85, and you burn more gallons to go the same distance.

That means the honest comparison isn't price per gallon — it's cost per mile.

The cost-per-mile rule

As a practical rule of thumb: E85 saves you money when it's priced at least 20–25% below regular gas. If E85 is only ~10% cheaper, the MPG hit usually wipes out the savings, and you actually pay more per mile.

Quick example. Say regular is $3.50/gal and your car gets 30 MPG on it — that's about 11.7¢/mile. On E85 you might get ~22 MPG (a ~27% drop). For E85 to break even at that economy, it needs to cost about $2.57/gal — roughly 26% cheaper. Below that price, E85 wins; above it, you're paying for the privilege.

Why the spread changes constantly

E85 pricing swings harder and more locally than regular gas, and the ethanol content itself isn't fixed — E85 is legally 51–83% ethanol and drops in winter, which changes both its price and its energy content. So a deal that worked last week can be a loss today. (More on that in why your "E85" isn't 85% ethanol.)

The easy way to know before you fill

Doing this math at the pump is annoying, which is exactly why we built it into E85 App: it shows freshness-dated E85 prices near you and compares the true per-mile cost against regular, so a "cheap" pump that isn't actually cheaper can't fool you. It's free on iPhone.

So — is it worth it?

For flex-fuel vehicle owners, E85 is worth it when the local price is 20–25%+ below regular, and it's a clear win for tuners chasing E85's ~100–105 octane for cheap. For everyone else, check the per-mile cost before you commit a tank. And remember: only flex-fuel vehicles (FFVs) should run E85 — confirm compatibility first.

Related: How to find E85 near you · How to blend E85 to E30/E50