Fuel mix calculator
Type an amount of fuel and a ratio to see how much two-stroke oil that is, in litres, US gallons and imperial gallons.
Checked against the sources at the bottom of this page on October 8, 2026. Published tables are revised: the source has the last word.
Work it out
How the answer is worked out
Oil volume = fuel volume divided by the ratio number. In a ratio written N:1, the N is the parts of fuel for each 1 part of oil.
The oil is then shown in other units. 1 US gallon is 3.785412 litres, 1 imperial gallon is 4.54609 litres and 1 US fluid ounce is 29.57353 millilitres, as NIST prints them.
What the sources say
The ratio is whatever is typed. This page suggests no ratio and holds no list of ratios: the owner manual for a saw states the ratio and the oil standard for that saw, and this page does not.
NIST lists the Canadian and U.K. gallon as exactly 4.54609 litres, and the U.S. gallon and U.S. fluid ounce to seven figures, in its Appendix B.8 conversion factors. NIST's footnotes to Appendix B record that the litre has been the special name for the cubic decimetre since 1964.
The fuel box takes the fuel alone. The finished mix is the fuel plus the oil, so it is a little larger than the number typed.
Arithmetic only. The answer is only as good as the numbers entered. It is not a plan or a safe working load for any job.
Sources
- NIST, Guide for the Use of the International System of Units (SP 811), Appendix B.8 factors for units listed alphabetically, read October 8, 2026
- NIST, Guide for the Use of the International System of Units (SP 811), Appendix B.9 factors for units listed by kind of quantity, read October 8, 2026
- NIST, Guide for the Use of the International System of Units (SP 811), footnotes to Appendix B, read October 8, 2026