Enter the price per liter of ethanol and gasoline below and click Calculate. The calculator applies the 70% rule and tells you which fuel is more economical.
Ethanol vs Gasoline Calculator
Enter prices per liter. Use a period or comma for decimals.
Result:
How to use the calculator
- Enter the ethanol price per liter at the pump.
- Enter the gasoline price per liter at the pump.
- Click Calculate to see which fuel is more economical.
The 70% rule
Flex-fuel vehicles achieve on average 70% of the mileage on ethanol compared to gasoline. This means that for every liter of ethanol, you travel roughly 70% of the distance you would with a liter of gasoline.
The comparison is straightforward:
If ethanol / gasoline ≤ 0.70 → fill up with ethanol
If ethanol / gasoline > 0.70 → fill up with gasoline
Note: the 70% figure is a general guideline. Check your vehicle's manual for the exact efficiency ratio of your model.
Practical examples
| Ethanol ($/L) | Gasoline ($/L) | Ratio | Conclusion |
|---|---|---|---|
| $0.99 | $1.49 | 66.4% | Ethanol wins |
| $1.10 | $1.49 | 73.8% | Gasoline wins |
| $1.04 | $1.49 | 69.8% | Ethanol wins (borderline) |
| $0.90 | $1.40 | 64.3% | Ethanol wins |
| $1.15 | $1.55 | 74.2% | Gasoline wins |
Frequently asked questions
When is it worth filling up with ethanol?
Ethanol is the better choice when its price per liter divided by the gasoline price per liter is less than or equal to 0.70 (70%). Below this threshold, the cost per kilometer is lower with ethanol.
Why is the limit 70%?
Flex-fuel vehicles average about 30% less mileage on ethanol. If ethanol costs up to 70% of gasoline, the cost per km is equivalent. Above that, gasoline becomes more economical.
Does the rule apply to all flex-fuel vehicles?
The 70% rule is a reliable estimate for most flex-fuel vehicles. Some models have slightly different efficiency — consult your vehicle's manual for a precise figure.
How do I calculate manually?
Divide the ethanol price by the gasoline price. If the result is ≤ 0.70, choose ethanol. Example: $1.00 ÷ $1.50 = 0.667 → ethanol is worth it.
Does the calculator work for blended ethanol (e.g. E85)?
Yes. Enter the price of whichever fuel type you are comparing — the comparison logic is the same as long as you use the correct efficiency ratio for your vehicle.
See also…
