Calculate the air-fuel ratio and lambda relative to gasoline’s 14.7:1 stoichiometric mix.
| AFR | – |
| λ (vs 14.7) | – |
Use this calculator at the dyno or when a wideband AFR reading needs a λ check against a gasoline baseline.
The calculation is: AFR = air mass ÷ fuel mass, and λ = AFR ÷ 14.7. Air and fuel must use the same mass unit, such as kilograms (kg) or pounds (lb). The unit selector is handled automatically, so you can use kg or lb for both mass inputs. Diesel and alcohol stoichiometric values differ; this tool does not switch fuels.
Air mass: Mass of air in the mixture, in kg or lb.
Fuel mass: Mass of fuel in the same unit. At gasoline stoich, 14.7 units of air go with 1 unit of fuel.
AFR: Air-fuel ratio by mass. Gasoline stoich is 14.7.
λ (vs 14.7): Lambda relative to 14.7. Values below 1 are rich; values above 1 are lean.
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