Is E85 actually cheaper than gas?

The short answer: E85 is cheaper per gallon almost everywhere, but that isn't the same as cheaper to drive. Ethanol carries roughly 27% less energy than gasoline, so you burn more of it to cover the same distance. A 15% discount on E85 with a 25% MPG loss means you're paying more per mile while feeling like you got a bargain.

The good news is that there's a single number that settles it for your car, and you can work it out at the pump in about five seconds.

What regular gas has to cost for E85 to win, by state

We measure E85 prices continuously, but we don't measure regular gasoline — so rather than guess at your local gas price and hand you a verdict built on it, here's the question inverted: given what E85 actually costs in your state today, what would regular have to cost before E85 becomes the cheaper way to drive?

Compare the right-hand column against the price on the sign at any gas station near you. If regular is above it, E85 wins where you live.

Median E85 price per state, July 27, 2026. Break-even assumes a 25% MPG loss — adjust it for your own car in the calculator. States with fewer than 10 priced stations are excluded. Full data: E85 price index.

Why price per gallon is the wrong comparison

A gallon of gasoline holds roughly 114,000 BTU. A gallon of E85 holds about 82,000. Your engine converts energy into distance, not dollars into distance, so the fuel with less energy in it takes you fewer miles — and that gap, close to 27%, is the entire reason this question is more complicated than reading two signs.

The comparison that means something is cost per mile:

cost per mile = price per gallon ÷ MPG on that fuel

Run it for both fuels and buy the lower number. Everything else in this article is a shortcut to avoid doing that arithmetic at the pump.

The break-even price, worked through

Rearranging the cost-per-mile comparison gives you the price at which the two fuels cost exactly the same to drive:

break-even E85 price = regular price × (E85 MPG ÷ gas MPG)

Say you get 20 MPG on gasoline and 15 on E85 — a 25% loss — and regular is $3.50:

$3.50 × (15 ÷ 20) = $2.63

At $2.63 the two fuels are identical to run. Below it, every gallon of E85 saves you money. Above it, you're paying a premium for the privilege of filling up more often. Note how demanding that is: E85 at $2.99 against gas at $3.50 looks like a 15% saving and is actually a loss.

How much MPG will you actually lose?

Between 15% and 27%, and where you land depends mostly on your engine.

Stock, naturally aspirated

Expect close to the full energy penalty — 22–27%. There's no mechanism to recover it. The ECU adds fuel to hold the air-fuel ratio and that's the end of the story. Most flex-fuel trucks and SUVs live here.

Turbocharged, tuned for ethanol

Often 15–20%. E85's high effective octane and strong charge-cooling let a tune run more timing and boost, recovering some efficiency along with the extra power. This is why E85 is popular with tuners even when the fuel economics are neutral — you're buying knock resistance, and the cost comparison is only half the picture.

Measure it instead of trusting a table

Two tanks gives you a real number. Run one full tank of gasoline, note the MPG, then one full tank of E85 and note that. Your figure accounts for your engine, your right foot and your commute — all of which matter more than any published average. Put it into the calculator and the answer becomes specific to you rather than to a hypothetical driver.

When E85 is not cheaper

Worth being blunt about, because most articles on this question quietly skip it.

• When the discount is under about 20%. This is the common case on the coasts. E85 at 10–15% below regular is a straightforward loss for most stock vehicles.
• When you have to drive to find it. E85 stations are far sparser than gas stations — the median distance from one E85 pump to the next nearest is under two miles in dense areas but climbs past nine at the 90th percentile. An eight-mile detour can wipe out the entire saving on a 15-gallon fill.
• When you fill up rarely. The saving scales with gallons burned. If you drive 5,000 miles a year, even a good discount is worth a few tens of dollars annually — probably not worth reorganising your routine around.
• When your tank is small. A 25% range reduction on a 12-gallon tank means noticeably more stops, which is a real cost in time even when it's a win in money.
• When you're comparing against your car's actual requirement. If your car happily runs 87 octane, you're comparing E85 to the cheapest fuel on the forecourt, which is the hardest comparison for E85 to win.

Where E85 is most convincing: against premium

If your car requires premium, the calculation changes considerably in E85's favour. You're no longer comparing against the cheapest fuel on the forecourt but against the most expensive, and premium typically carries a $0.60–$1.00 per gallon markup over regular.

Because the break-even scales with the price of the fuel you're replacing, a higher baseline makes the threshold far easier to clear. And E85's effective octane is higher than pump premium, so you aren't trading performance for economy — which is the trade that usually makes cheaper fuel a false saving.

E85 vs E15 vs premium, briefly

E15 (sold as Unleaded 88) is about 15% ethanol. The energy penalty is small — roughly 4–5% — and it's typically priced a few cents under regular, so it's usually a mild net win with none of the range implications. It's a different proposition from E85 rather than a smaller version of it.

Premium is worth buying only if your engine requires it or a tune uses it. If you're paying for premium your car doesn't need, that's a straightforward loss, and E85 in a flex-fuel vehicle is very likely to beat it.

E85 is the highest-variance option: the biggest per-gallon discount, the biggest energy penalty, and the most sensitive to local pricing. Which is why it needs a calculation and the others mostly don't.

Two things that quietly change the math

Winter blends work in your favour

Pump E85 isn't a fixed 85% ethanol — ASTM D5798 permits 51–83%, and suppliers weaken it in winter so engines start in the cold, sometimes to E51. Less ethanol means less energy loss, so your MPG penalty shrinks while the price usually doesn't. Winter E85 is often a quietly better deal than summer E85. (More: your E85 isn't 85%.)

Only flex-fuel vehicles need apply

None of this matters unless your car is a factory FFV. Running E85 in a vehicle that wasn't built for it damages fuel-system components and runs the engine lean — a repair bill that dwarfs any fuel saving. Check the flex-fuel vehicle list first.

Frequently asked questions

Is E85 actually cheaper than regular gas?

Sometimes. E85 is almost always cheaper per gallon — the national median is $2.99 as of July 27, 2026 — but it contains about 27% less energy, so you burn more of it. It only saves money when the per-gallon discount is bigger than your MPG loss. As a rule of thumb, E85 needs to be roughly 20–25% below regular before you're actually ahead.

How do I work out if E85 is cheaper for my car?

Compare cost per mile: divide each fuel's price per gallon by the MPG you get on it. Or use the shortcut — multiply the E85 price by 1.33 and compare that to regular. If regular costs more than that number, E85 wins.

How much money does E85 actually save?

Realistically, when the discount is good, somewhere between 3 and 8 cents a mile — roughly $400–$900 a year at 12,000 miles. When the discount is thin it saves nothing, and when it's under about 20% you lose money. It is not the 20–30% saving the pump price implies.

Why is E85 cheaper per gallon in the first place?

Ethanol is produced domestically from corn and is cheaper to make than refined gasoline, and it's supported by federal blending policy. Prices are lowest close to Midwest production and rise with distance and state fuel taxes — which is why the state spread is so wide.

Does E85 save money in a non-tuned car?

It can, but it's purely a price question on a stock flex-fuel vehicle: run the break-even number and buy whichever is cheaper per mile. Tuning changes the calculation because it converts E85's octane into power, which is a benefit that doesn't show up in a fuel-cost comparison at all.

Is E85 cheaper than premium?

Almost always by a wide margin per gallon, and this is where E85 is most compelling. If your car requires premium, you're comparing E85 against a much more expensive baseline, so the break-even is far easier to clear — and E85's effective octane is higher than pump premium.

Does E85 cost more in winter?

The pump price doesn't necessarily change, but the economics quietly improve. Winter blends contain less ethanol — as low as E51 — which means less energy loss, so your MPG penalty shrinks. You're getting more gasoline for the same E85 price.

What is the cheapest state for E85?

North Dakota, at a median of $2.32/gal across 29 stations. The most expensive is Connecticut at $5.09. See the full ranking above, or the live E85 price index.

More: run your own numbers · live E85 price index · E85 gas mileage · find E85 near you