Inputs
A wrong input makes a wrong estimate.
- Enter current fuel amount, current ethanol, target ethanol, and fill amount.
- Use manual values when you want to plan a one-off fill.
- Review every value before using the result.
Ethanol calculator
Start with what is in the tank now.
Enter the current fuel amount and ethanol content, your target, and how much you plan to add. Idle returns an estimate—not a recommendation for what your car can run.
The calculation
Four inputs in. An estimate out.
Save recurring values to the vehicle, or enter them manually for a one-off fill. Review every number before you use the result.
Garage defaults
Save the recurring numbers to the car.
- Save tank size, pump gas, ethanol defaults, and notes for your own garage vehicles.
- Update saved values when your setup, tune, or fuel plan changes.
- Keep build-specific fuel notes with the vehicle they belong to.
Before you drive
Your setup decides what is safe. The calculator does not.
- Confirm station details, fuel availability, and hours before driving.
- Only use blends your vehicle, tune, and parts support.
- When something looks off, check the numbers before filling up.
Questions
What the result means
The calculator handles the mix from your inputs. It does not inspect your tune, parts, or station fuel.
What does Idle's ethanol calculator do?
Idle's ethanol calculator estimates blend amounts from the current fuel, current ethanol, target ethanol, fill amount, and vehicle defaults you enter.
Can I use saved vehicle fuel details?
Yes. You can save useful fuel details for your own garage vehicles, such as tank size, pump gas, ethanol defaults, and notes, then use them when planning a blend.
Does the calculator know what my car can safely run?
No. The calculator is a planning tool from your inputs. Only use blends your vehicle, tune, and parts support.
Does Idle guarantee E85 station availability?
No. Confirm station details, fuel availability, and hours before driving.
Run the estimate before the pump.
Open the calculator in Idle, review each value, and use only a blend your vehicle supports.