Mixing Ratios Made Easy: 2-Stroke Fuel, Paint, Epoxy and Cleaning Solutions

Small engines, two-part resins, paint thinners and concentrated cleaners all come with a mixing ratio on the label. Get it wrong and an engine seizes, epoxy stays sticky or a cleaner is too weak to work. The math is the same for all of them.

How to read a mixing ratio

A ratio such as 50 : 1 means 50 parts of the first ingredient to 1 part of the second. For two-stroke fuel, that's 50 parts gasoline to 1 part oil. A 2 : 1 epoxy means 2 parts resin to 1 part hardener. Always check whether the label means by volume or by weight; most epoxies specify one or the other and they are not interchangeable.

Two-stroke fuel

oil = fuel amount ÷ ratio

One US gallon is 128 fluid ounces, so:

Follow your equipment manufacturer's ratio; using a different one can affect lubrication and warranty coverage.

Two-part epoxy and resins

Common ratios are 1 : 1, 2 : 1 and 3 : 1. To make 300 ml of a 2 : 1 epoxy, there are 3 parts of 100 ml each: 200 ml resin and 100 ml hardener. Measure accurately and mix thoroughly; unlike fuel, extra hardener does not make epoxy "stronger" and often leaves it soft or brittle.

Dilution ratios for cleaners

Labels may say "1 : 10" or "1 part to 10 parts water." That's 11 parts in total. For a 1-liter spray bottle: 1,000 ÷ 11 ≈ 91 ml concentrate and 909 ml water. Some labels instead say "dilute 1 in 10," meaning 1 part out of 10 total, which is 100 ml concentrate and 900 ml water. The difference is small here but grows with stronger mixes, so read carefully.

Paint and thinner

Spray painting often calls for thinning paint by a percentage, such as 10%. That's a ratio of 10 : 1 paint to thinner. For a quart (32 fl oz) of paint, add 3.2 fl oz of thinner. If the instruction is "thin to 10% of the final mix," it's 9 : 1 instead. When in doubt, add less and test.

Concrete and mortar

Construction mixes use three-part ratios by volume, such as 1 : 2 : 3 cement : sand : gravel for concrete. See concrete mix ratios explained for strengths and quantities.

Measuring small amounts accurately

• Use a graduated cup or syringe marked in milliliters for small volumes.
• Measure by weight with a kitchen scale when the label gives a weight ratio.
• Mix a larger batch if your measuring tools are imprecise at small volumes, as long as you can use or store it safely.
• Label mixed containers with the ratio and date.

Calculate any mix

Enter the ratio in the ratio calculator and use "Divide a total" to split a batch size, or "Scale" to set one ingredient and find the rest.