About this site

Two-stroke mixing is simple arithmetic that people get wrong in expensive ways. Guess lean and a chainsaw seizes; guess rich and the plug fouls and the exhaust carbons up. Most of the answers online are a single number for a single ratio, buried in a forum thread, in units you do not use.

So this site does three things: it calculates the exact oil for any fuel amount at any ratio in both US and metric units, it publishes printable reference charts for the common ratios, and it explains the context around each ratio and each class of equipment so the number actually means something.

It is an independently run site, built and maintained by one person rather than a media company. It is not affiliated with, endorsed by, or sponsored by Stihl, Husqvarna, Echo, AMSOIL, Mercury, Yamaha or any other manufacturer named on the site. Brand names appear because readers own those machines, not because anyone paid for the mention.

Corrections and questions go to hello@2cycleoilmixcalculator.com, and the contact page explains what is useful to include.

Every oil figure on this site comes from one piece of arithmetic, applied in one place in the code: oil = fuel divided by the ratio. One US gallon is 128 fluid ounces and one litre is 1000 millilitres, so 50:1 is 128 ÷ 50 = 2.56 oz per gallon and 1000 ÷ 50 = 20 ml per litre.

No figure in the prose, the charts or the calculator is typed by hand. They are all generated from that single calculation at build time, which is why the sentence in an article, the row in a chart and the answer from the calculator can never disagree with each other.

Ratios attributed to a manufacturer come from that manufacturer's published specifications and manuals. Oil standards are described from the standards themselves: JASO FB, FC and FD for air-cooled engines, NMMA TC-W3 for water-cooled outboards, ISO-L-EGD, and the older API TC.

We do not run bench tests, dyno tests or teardowns, and we do not claim to. Where an article ranks or recommends an oil, it is doing so on published specification and general availability, and it says so. Any statement that reads like a test result would be a fabrication, so you will not find one here.

• Your engine's decal and manual outrank anything on this site. Where a general rule and a manual disagree, follow the manual.
• Where a spec varies by model year or market, the page says so instead of picking a number and presenting it as universal.
• Pages are updated when specifications change or when a reader sends a correction, and the underlying arithmetic is shared across the whole site so a fix lands everywhere at once.
• Content is written to be useful without buying anything. Affiliate links and ads pay for hosting, and they never decide what a page recommends.

The calculator and charts are free and always will be. Running costs are covered by display advertising and by affiliate links to products readers were going to buy anyway, at no extra cost to them. The disclosures are set out in full on the privacy and disclosure page.

The important boundary: a product does not appear on a page because it earns a commission. If the honest answer to a question is that the cheap bottle at the hardware store is fine, that is what the page says.