DIY Cost Tools
Two-Stroke Oil Mix Calculator
Calculate two-stroke oil quantity for a gasoline volume and manufacturer-specified fuel-to-oil ratio.
How to use this calculator
- Replace every example value with your own measurements, label values or planning assumptions.
- Keep each value in the unit printed beside its field.
- Select Calculate, then compare the result with the formula and limitations below.
Formula and method
Oil fluid ounces = gasoline gallons × 128 ÷ fuel-to-oil ratio. Milliliters = fluid ounces × 29.5735; liters = milliliters ÷ 1,000.
Results are hidden whenever an input changes or validation fails, so an older answer cannot be mistaken for the current calculation.
Worked example
Gasoline volume = 5 US gal; Fuel-to-oil ratio = 50. The calculator returns Oil required = 12.8 US fl oz; Oil required = 379 mL; Oil required = 0.379 L.
The worked example uses the same default values displayed in the calculator.
Limitations and safety
Frequently asked questions
What should I enter first?
Start with measurements or rates from the project, product label, service quote or equipment specification. Replace every example value before relying on the estimate.
Why can the real result differ?
Use only the ratio and oil type specified for the exact engine. Work away from ignition sources, use an approved fuel container, measure accurately and follow fuel-storage and environmental rules.
Does the calculator round purchases up?
Only outputs labeled as whole packages, vents, heaters, pails or similar counts are rounded up. Keep extra precision for planning and follow supplier packaging.
Review notes and reference
Reviewed October 5, 2026. The formula was independently checked against the displayed default example, and the calculator was tested for valid defaults, empty input, invalid formats, range boundaries and recovery. Reference: NIST SI Units. Explanations and examples are original.