Air Fuel Ratio Calculator
Air-fuel ratio, lambda and equivalence ratio from air and fuel mass flow.
Compare Your Options And Get Clear Answers
Air-fuel ratio, lambda and equivalence ratio from air and fuel mass flow.
Air Fuel Ratio Estimator
Enter your numbers below for an instant estimate.
How It Works
Key concepts behind this calculator
Enter Values
Fill in each field with your own numbers.
Calculate
Results update as you change the inputs.
Review
Read the breakdown and the explanation.
Adjust
Change values to compare scenarios.
Air Quick Guide
Typical values for reference.
| Air g/s | Fuel g/s | Stoich | AFR |
|---|---|---|---|
| 30 | 2 | 14.7 | 15.00 : 1 |
| 50 | 3.4 | 14.7 | 14.71 : 1 |
| 80 | 6 | 14.7 | 13.33 : 1 |
| 100 | 7.5 | 14.7 | 13.33 : 1 |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Air Fuel Ratio Calculator FAQ
Answers to common questions about this calculator.
AFR divided by the stoichiometric AFR; 1.0 is chemically ideal.
Lambda below 1, with more fuel than ideal.
AFR = air mass / fuel mass; lambda = AFR / stoichiometric AFR.
It is an estimate based on the inputs you enter. Check real quotes, labels or official guidance for important decisions.