Oil to Gas Ratio Calculator

When preparing fuel mixture for a motorized equipment requiring a 40:1 ratio, oil to gas ratio calculator specify that 1 gallon of gasoline needs 3.2 ounces of two-stroke oil.

Oil to Gas Ratio Conversion Table

Oil to Gas Ratio Formula

The essential mixing formula is structured as:

Oil Amount = Gas Amount ÷ Ratio Number

For different measurement systems:

US measurements:

Oil (oz) = Gas (gallons) × 128 ÷ Ratio Number

Metric system:

Oil (ml) = Gas (liters) × 1000 ÷ Ratio Number

Basic Oil to Gas Ratio Formula:

OGR = (Volume of Oil) / (Volume of Natural Gas)

Typically measured in barrels of oil per million cubic feet of gas (BBL/MMCF)

Volumetric OGR Calculation:

OGR (BBL/MMCF) = (Oil Production Rate) / (Gas Production Rate) × Conversion Factor

Mass-Based OGR Calculation:

Mass OGR = (Mass of Oil Produced) / (Mass of Gas Produced)

In a practical example using a 50:1 ratio with 2 gallons of gas:

Oil needed = 2 × 128 ÷ 50 = 5.12 ounces

How to Convert Oil to Gas Ratio

The conversion process:

• Identify your target ratio (e.g., 40:1)
• Apply the unit conversion factor to fuel volume
• Calculate oil quantity using the ratio number

Converting 5 liters of fuel at 32:1 ratio:

Oil needed = 5 × 1000 ÷ 32 = 156.25 ml

• String Trimmer (50:1): Fuel: 1 gallon, Result: 128 ÷ 50 = 2.56 oz oil
• Power Saw (40:1): Fuel: 2 liters, Result: 2000 ÷ 40 = 50 ml oil
• Boat Engine (25:1): Fuel: 5 gallons, Result: (5 × 128) ÷ 25 = 25.6 oz oil
• Motorcycle (32:1): Fuel: 3 liters, Result: 3000 ÷ 32 = 93.75 ml oil
• Winter Vehicle (45:1): Fuel: 4 gallons, Result: (4 × 128) ÷ 45 = 11.38 oz oil

What is Oil to Gas Ratio?

The mixture ratio defines the relationship between fuel and two-stroke oil. This measurement applies specifically to two-stroke engines, which differ from four-stroke motors by requiring oil-fuel mixture for internal lubrication. Modern equipment typically uses ratios from 16:1 to 50:1, with newer engines favoring higher ratios due to technological advances.