🫠 Gas Oil Ratio Calculator
Enter your gas amount and desired mix ratio to find exactly how much 2-stroke oil to add.
What is a gas-oil ratio?
Two-stroke engines (found in chainsaws, weed trimmers, some outboards, and dirt bikes) mix oil directly into the gasoline for lubrication, since they lack a separate oil sump. The ratio (like 50:1) tells you how many parts gasoline per one part oil.
The formula
This calculator converts your gasoline amount to fluid ounces (1 gallon = 128 fl oz), then divides by the mix ratio to find Oil Needed = Gasoline (fl oz) ÷ Ratio, also shown in milliliters for oil bottles marked in metric units.
Always use the mix ratio specified by your equipment’s manufacturer — using the wrong ratio can cause poor lubrication (engine damage) or excess smoke and carbon buildup (too much oil). This tool is for general reference only.