2-Stroke Oil Gas Mix Chart: 50:1, 40:1, 32:1 Ounces Per Gallon
A gallon of gas at 50:1 takes 2.56 fluid ounces of two-stroke oil (76 mL). At 40:1 it is 3.2 oz, at 32:1 4 oz, and at 25:1 5.12 oz. The ratio is parts of gasoline to one part of oil, so the oil is the gasoline divided by the ratio. The two-stroke fuel mix calculator does any amount or ratio.
Oil per gallon, by ratio
For one US gallon (128 fluid ounces) of gasoline:
| Ratio | Oil (fl oz) | Oil (mL) | Oil (tablespoons) | Oil in the mix |
|---|---|---|---|---|
| 16:1 | 8.00 oz | 237 mL | 16.0 tbsp | 5.9% |
| 20:1 | 6.40 oz | 189 mL | 12.8 tbsp | 4.8% |
| 25:1 | 5.12 oz | 151 mL | 10.2 tbsp | 3.8% |
| 32:1 | 4.00 oz | 118 mL | 8.0 tbsp | 3.0% |
| 40:1 | 3.20 oz | 95 mL | 6.4 tbsp | 2.4% |
| 50:1 | 2.56 oz | 76 mL | 5.1 tbsp | 2.0% |
| 80:1 | 1.60 oz | 47 mL | 3.2 tbsp | 1.2% |
| 100:1 | 1.28 oz | 38 mL | 2.6 tbsp | 1.0% |
Oil for different amounts of gas
US fluid ounces of oil:
| Gasoline | 25:1 | 32:1 | 40:1 | 50:1 | 100:1 |
|---|---|---|---|---|---|
| 0.25 gal | 1.28 oz | 1.00 oz | 0.80 oz | 0.64 oz | 0.32 oz |
| 0.5 gal | 2.56 oz | 2.00 oz | 1.60 oz | 1.28 oz | 0.64 oz |
| 1 gal | 5.12 oz | 4.00 oz | 3.20 oz | 2.56 oz | 1.28 oz |
| 2 gal | 10.24 oz | 8.00 oz | 6.40 oz | 5.12 oz | 2.56 oz |
| 2.5 gal | 12.80 oz | 10.00 oz | 8.00 oz | 6.40 oz | 3.20 oz |
| 5 gal | 25.60 oz | 20.00 oz | 16.00 oz | 12.80 oz | 6.40 oz |
Metric: milliliters of oil per liter of gas
| Gasoline | 25:1 | 32:1 | 40:1 | 50:1 |
|---|---|---|---|---|
| 1 L | 40 mL | 31 mL | 25 mL | 20 mL |
| 2 L | 80 mL | 62 mL | 50 mL | 40 mL |
| 4 L | 160 mL | 125 mL | 100 mL | 80 mL |
| 5 L | 200 mL | 156 mL | 125 mL | 100 mL |
| 10 L | 400 mL | 312 mL | 250 mL | 200 mL |
| 20 L | 800 mL | 625 mL | 500 mL | 400 mL |
How to mix it
- Check the ratio in the engine manual or on the tank cap. Use it exactly: lean mixtures can seize the engine, rich ones foul the plug.
- Use fresh gasoline, and an oil made for two-stroke air-cooled engines (look for JASO FD or ISO-L-EGD).
- Pour the oil into an approved fuel can first, add about half the gasoline, close the cap and shake, then add the rest.
- Label the can with the ratio and the date. Mixed fuel goes stale in a month or two, sooner with ethanol blends.
- Fill the tool in a well-ventilated place, with the engine off and cool.
Common mistakes
- Using 4-stroke motor oil, which is not made to burn with the fuel.
- Pouring the oil into the tool's tank first, then adding gas, which does not mix evenly.
- Mixing a big batch that sits all season. Mix what you will use in a few weeks.
- Mixing up gallons and liters: a liter is a bit over a quarter of a gallon (0.26 gal).
For sprayers, see the sprayer mix calculator. Estimates only: follow the engine maker's instructions.
Frequently asked questions
How much oil for 1 gallon of gas at 50:1?
2.56 fluid ounces (76 mL, about 5.1 tablespoons).
How much oil for 1 gallon of gas at 40:1?
3.2 fluid ounces (95 mL). At 32:1 it is 4 ounces, and at 25:1 5.12 ounces.
How much oil for 5 gallons of gas at 50:1?
12.8 fluid ounces (379 mL).
How much oil for 5 liters of gas at 50:1?
100 mL: 20 mL for each liter.
What ratio is 3.2 ounces to a gallon?
40:1, because a gallon is 128 ounces and 128 ÷ 3.2 is 40.
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.