Ethanol vs Gas: Which Saves Money for Brazilian Drivers
Compare ethanol and gas costs with our fuel calculator. Learn the 70% rule and save up to R$200 monthly on fuel expenses in Brazil.
The choice between ethanol and gasoline can result in significant savings in a driver’s monthly budget. With fuel price differences constantly fluctuating, knowing which option pays off more is essential for reducing costs.
Our fuel calculator allows you to quickly compare which option is most advantageous based on current prices and your vehicle’s fuel efficiency.
Ethanol vs Gasoline: which to choose
Ethanol and gasoline have distinct characteristics that directly impact the cost per kilometer driven. The right decision can generate savings of up to R$200 monthly for those who drive frequently.
Differences between fuels
The calorific power is the main technical difference between fuels:
- Gasoline: higher energy per liter, better fuel efficiency
- Ethanol: lower energy per liter, 25-30% higher consumption
- Price: ethanol generally cheaper than gasoline
Factors that influence the choice
Several elements affect which fuel will be more economical:
- Price per liter at gas stations in your region
- Specific consumption of your vehicle with each fuel
- Monthly mileage you drive
- Type of route (city or highway)
The 70% rule explained
The famous 70% rule is a quick method to decide between ethanol and gasoline. It works as an initial reference, but isn’t always accurate.
How the calculation works
The rule determines that ethanol is worthwhile when its price is up to 70% of gasoline’s value:
Example: Gasoline at R$5.50 × 0.70 = R$3.85 If ethanol is below R$3.85, it theoretically pays off
When ethanol is worth it
The 70% rule considers that ethanol has 30% lower efficiency than gasoline. However, each vehicle behaves differently:
- Modern flex cars: may have less than 30% difference
- Older vehicles: difference may be greater than 30%
- Usage conditions: heavy traffic affects ethanol efficiency more
Calculating cost per kilometer
The precise calculation considers price and actual consumption of each fuel. It’s the only way to make the right decision.
Price per liter
Compare current prices at gas stations near your region:
| Fuel | National Average Price (2024) |
|---|---|
| Gasoline | R$5.40 - R$5.80 |
| Ethanol | R$3.20 - R$4.20 |
Vehicle consumption
Note your car’s actual consumption with each fuel:
- Fill up completely
- Drive at least 300 km
- Calculate: kilometers ÷ liters = km/liter
Comparative efficiency
Compare the cost per kilometer of each fuel:
- Gasoline: Price ÷ Consumption = Cost/km
- Ethanol: Price ÷ Consumption = Cost/km
Example: Gasoline R$5.50 ÷ 12 km/l = R$0.46 per km Ethanol R$3.80 ÷ 9 km/l = R$0.42 per km Savings with ethanol: R$0.04 per km
Practical calculation example
Let’s simulate a real scenario with a popular vehicle to demonstrate the economic difference between fuels.
Simulation with real prices
Example data:
- Vehicle: HB20 1.0 flex
- Prices: Gasoline R$5.60 | Ethanol R$3.90
- Consumption: 13 km/l (gasoline) | 9.5 km/l (ethanol)
Cost per km calculation:
| Fuel | Calculation | Cost/km |
|---|---|---|
| Gasoline | R$5.60 ÷ 13 km/l | R$0.431 |
| Ethanol | R$3.90 ÷ 9.5 km/l | R$0.411 |
Monthly savings
For those who drive 1,500 km monthly, the savings would be:
- Difference per km: R$0.431 - R$0.411 = R$0.02
- Monthly savings: 1,500 km × R$0.02 = R$30.00
- Annual savings: R$360.00
Other important factors
Besides cost, other aspects influence the choice of ideal fuel for your usage profile.
Engine performance
Performance varies between fuels:
- Gasoline: easier cold starts, less wear
- Ethanol: higher power in prepared engines, superior octane rating
- Maintenance: ethanol can be more aggressive to fuel system
Environmental considerations
Environmental impact can also influence your decision:
- Ethanol: renewable fuel, lower CO₂ emissions
- Gasoline: fossil fuel, greater environmental impact
- Sustainability: ethanol contributes to circular economy
Tips to save fuel
Regardless of your choice, these practices reduce consumption:
- Keep tires properly inflated at correct pressure
- Drive economically: accelerate gradually
- Perform preventive engine maintenance regularly
- Avoid excess weight in the vehicle
- Plan routes to reduce mileage
- Use air conditioning moderately at low speeds
Use our fuel calculator to simulate different scenarios and find the most economical option for your profile.
Frequently Asked Questions
How do I know if my car performs better with ethanol or gasoline?
Do a practical test: fill up completely with one fuel, drive 300-400 km and calculate consumption (km ÷ liters). Repeat with the other fuel and compare cost per kilometer.
Does the 70% rule always work?
No. The rule is just an initial reference. Each vehicle has different efficiency, so it’s essential to calculate based on your car’s actual consumption to make the right decision.
Is it worth mixing ethanol and gasoline?
It’s technically possible in flex cars, but not recommended. The mixture can affect performance and engine calibration. It’s better to use one fuel at a time.
How do fuel prices vary throughout the year?
Prices follow seasonal patterns: gasoline tends to rise in summer (higher demand), while ethanol gets more expensive during sugarcane off-season (May-September). Monitor regional prices.
My car consumes much more ethanol than gasoline. Is this normal?
Yes, it’s normal for ethanol to have 25-35% higher consumption than gasoline due to lower calorific power. If the difference is much greater, it may indicate injection system problems.
Can I use only ethanol in flex cars?
Yes, flex cars can run on ethanol only. However, always keep a minimum of gasoline in the tank (about 20%) to facilitate cold starts on very cold days.
How do I calculate monthly savings between fuels?
Multiply the cost per kilometer difference by your monthly mileage. Use our online calculator to automate this calculation and compare different scenarios.