AFR (Air-to-Fuel Ratio) Calculator
How do you calculate the air-to-fuel ratio for your engine? The AFR (Air-to-Fuel Ratio) Calculator can help you determine this important value with ease. Enter mass of air and fuel into calculator to find out AFR.
What Is AFR (Air-to-Fuel Ratio)?
AFR stands for Air-to-Fuel Ratio. It is the ratio of the mass of air to the mass of fuel in an internal combustion engine. This ratio is important for the performance of engine, fuel efficiency, and emissions control.
User Guide
To use the AFR calculator is simple . Here’s how you can do it:
- Enter Mass of Air (g): Input the mass of air in grams.
- Enter Mass of Fuel (g): Input the mass of fuel in grams.
- Enter AFR : 1: Input the AFR value.
Example Values
For example:
- Mass of Air: 14400 g
- Mass of Fuel: 1000 g
- AFR: 14.4 : 1
Formula
The formula to calculate AFR is:
| Variable | Description |
|---|---|
| Mass of Air | Mass of air in grams |
| Mass of Fuel | Mass of fuel in grams |
| AFR | Air-to-Fuel Ratio |
How To calculate – Examples
Example 1
- Mass of Air: 14400 g
- Mass of Fuel: 1000 g
Calculation:
AFR:
Result: The AFR is 14.4 : 1.
Example 2
- Mass of Air: 12000 g
- Mass of Fuel: 800 g
Calculation:
AFR:
Result: The AFR is 15 : 1.
Air to Fuel Ratio (AFR) Chart
| Fuel Type | Stoichiometric AFR | Rich Mixture AFR (more fuel) | Lean Mixture AFR (more air) |
|---|---|---|---|
| Gasoline | 14.7:1 | 10:1 | 16:1 |
| Diesel | 14.5:1 | 12:1 | 18:1 |
| Ethanol (E100) | 9:1 | 6:1 | 10:1 |
| Methanol | 6.4:1 | 4:1 | 7:1 |
| Propane | 15.67:1 | 11:1 | 17:1 |
| Natural Gas (Methane) | 17.2:1 | 12:1 | 19:1 |
| Hydrogen | 34:1 | 29:1 | 37:1 |
| E85 (85% Ethanol, 15% Gas) | 9.8:1 | 7:1 | 11:1 |
I hope you liked our AFR Calculator . How was your experience using the tool? If you are facing any errors, please report them on our “Report an Error” page.