Solve fuel ratios across air, oil, and blends. See conversions, percentages, and target quantities instantly. Clean visuals make complex ratio decisions easier every time.
The page stays in a single vertical flow, while inputs adapt into three, two, or one columns by screen size.
| Mode | Input Values | Key Output | Interpretation |
|---|---|---|---|
| Fuel-to-Air Analysis | Fuel = 5 kg, Air = 73.5 kg | AFR = 14.7, FAR = 0.068027 | This matches a classic stoichiometric gasoline ratio. |
| Air Needed from Fuel | Fuel = 8 kg, Target AFR = 12.5 | Required Air = 100 kg | Richer operation needs less air per fuel unit. |
| Fuel-Oil Mix Ratio | Fuel = 10 L, Ratio = 50:1 | Oil Needed = 0.2 L | Useful for two-stroke fuel preparation and blending. |
| Blend Split Ratio | Total = 100 L, Ratio = 3:2 | A = 60 L, B = 40 L | The total divides in direct proportion to parts. |
Fuel-to-Air Ratio: FAR = Fuel / Air
Air-to-Fuel Ratio: AFR = Air / Fuel
Fuel Share Percentage: Fuel% = Fuel / (Fuel + Air) × 100
Air Share Percentage: Air% = Air / (Fuel + Air) × 100
Lambda: Lambda = Actual AFR / Stoichiometric AFR
Equivalence Ratio: φ = Stoichiometric AFR / Actual AFR
Required Air: Required Air = Fuel × Target AFR
Fuel-Oil Mix: Oil Needed = Fuel / Mix Ratio
Blend Split: Component A = Total × A / (A + B) and Component B = Total × B / (A + B)
These formulas are ratio relationships, inverse relationships, and percentage transformations. They help convert one known quantity into the missing quantity.
A fuel ratio compares one fuel-related quantity with another. Common examples include fuel-to-air ratio, air-to-fuel ratio, fuel-to-oil ratio, and blend proportion between two components.
FAR divides fuel by air, while AFR divides air by fuel. They describe the same relationship from opposite directions, so one is the inverse of the other.
Stoichiometric AFR provides a reference point for complete combustion. Comparing actual AFR to stoichiometric AFR helps estimate lambda and equivalence ratio for richer or leaner mixtures.
Yes. The calculator displays results in the unit you choose. For correct ratios, keep input values within the same measurement system for that calculation mode.
Enter the fuel amount and the fuel-to-oil ratio, such as 50:1. The calculator divides fuel by the ratio number to find the oil needed.
Lambda compares actual AFR to stoichiometric AFR. A value of 1 is stoichiometric, below 1 is rich, and above 1 is lean.
Blend split mode takes a total quantity and allocates it by ratio parts. A 3:2 split means three-fifths of the total goes to A and two-fifths goes to B.
Use CSV when you want spreadsheet-ready values. Use PDF when you need a clean report for records, sharing, or printing.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.