Fuel-to-Air Ratio Calculator

The Reciprocal Convention for Mixture Ratio

Fuel-to-air ratio expresses the same mixture information as AFR, just inverted — fuel mass per unit of air mass rather than air per unit of fuel. Some combustion models and emissions calculations prefer this convention.

The Formula

Worked Example

15 kg of fuel supplied with 220 kg of air:

How to Use This Calculator

1. Enter the Mass of Fuel supplied.
2. Enter the Mass of Air supplied.
3. Select Calculate to get the FAR.

Related Calculations

Need the standard AFR convention instead? See the Air-Fuel Ratio (AFR) Calculator, or check the lambda equivalent in the Lambda Calculator.