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Gas or Ethanol

Find out whether gasoline or ethanol is more cost-effective. Calculated using the 70% rule. 100% free.

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Gas or Ethanol Calculator — Which Is Cheaper?

The Gas or Ethanol Calculator is a free online tool tailored to the Brazilian market that helps you determine whether it is more economical to fill up with gasoline (gasolina) or ethanol (etanol/álcool) based on current pump prices and your vehicle's consumption rates. In Brazil, where most vehicles are flex-fuel and both fuels are available at every gas station, choosing the right fuel can save hundreds of reais per year — and this calculator makes the decision instant and mathematical.Enter the price per liter of gasoline and ethanol at your gas station. The traditional rule of thumb says ethanol is worth it if its price is below 70% of gasoline's price (because ethanol delivers roughly 70% of gasoline's energy per liter). However, the real breakeven point varies by vehicle — some flex engines are more efficient on ethanol than others. Our calculator lets you customize the efficiency ratio if you know your car's specific consumption for each fuel, providing a more accurate recommendation than the generic 70% rule.Brazilian drivers use this tool before every fill-up to maximize savings. Fleet managers determine fuel policies for company vehicles. Taxi and ride-share drivers optimize fuel costs to maximize their earnings per kilometer. Students learning about energy economics use it to understand fuel efficiency comparisons. The tool is especially valuable when fuel prices fluctuate, as the optimal choice can change week to week or even station to station across different regions.This calculator is part of the facilita.tools collection of free Brazilian automotive utilities. Available in Portuguese, English, and Spanish, optimized for mobile use at the pump.

Frequently Asked Questions

What is the 70% rule for ethanol?
If the price of ethanol is less than 70% of the gasoline price, ethanol is more economical. This is because ethanol has about 70% of the energy content of gasoline.
Does this work for flex fuel vehicles?
Yes, this calculator is designed specifically for flex fuel vehicles that can run on both gasoline and ethanol.
Does the 70% rule always apply for ethanol vs gasoline?
The 70% rule is a simplified guideline: if ethanol costs less than 70% of gasoline, ethanol is more economical. However, the actual break-even point varies by vehicle (typically 70-75% for flex-fuel cars). Some newer engines achieve better ethanol efficiency, shifting the ratio closer to 75%.