40:1 fuel mix: how much oil per gallon?
For a 40:1 mix, add 3.2 fl oz (95 ml) of 2-stroke oil to each US gallon of gas, or 25 ml per liter. That is 2.5 % oil.
A 2.6 fl oz bottle of oil goes with 104 fl oz (3.08 L) of gas at 40:1.
40:1 oil per US gallons of gas
40:1 oil per US gallons of gas| Gas | Oil | In spoons |
|---|
| 1 gal | 3.2 fl oz (95 ml) | 6.4 tbsp · 19.2 tsp |
|---|
| 2 gal | 6.4 fl oz (189 ml) | 12.8 tbsp · 38.4 tsp |
|---|
| 2.5 gal | 8 fl oz (237 ml) | 16 tbsp · 48 tsp |
|---|
| 3 gal | 9.6 fl oz (284 ml) | 19.2 tbsp · 57.6 tsp |
|---|
| 5 gal | 16 fl oz (473 ml) | 32 tbsp · 96 tsp |
|---|
40:1 oil per liters of gas
40:1 oil per liters of gas| Gas | Oil |
|---|
| 1 L | 25 ml (0.8 fl oz) |
|---|
| 4 L | 100 ml (3.4 fl oz) |
|---|
| 5 L | 125 ml (4.2 fl oz) |
|---|
| 10 L | 250 ml (8.5 fl oz) |
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| 20 L | 500 ml (16.9 fl oz) |
|---|
Every common ratio, per gallon and per liter
Every common ratio, per gallon and per liter| Ratio | Oil per gallon | Oil per liter |
|---|
| 50:1 | 2.6 fl oz (76 ml) | 20 ml |
|---|
| 40:1 | 3.2 fl oz (95 ml) | 25 ml |
|---|
| 32:1 | 4 fl oz (118 ml) | 31 ml |
|---|
| 25:1 | 5.1 fl oz (151 ml) | 40 ml |
|---|
| 20:1 | 6.4 fl oz (189 ml) | 50 ml |
|---|
50:1 means 50 parts gas to 1 part oil: oil = gas ÷ 50, gas = oil × 50. 1 US gal = 128 fl oz = 3.785 L; 1 imperial gal = 4.546 L. Spoons are US: 1 tbsp = 1/2 fl oz, 1 tsp = 1/6 fl oz.
Estimates. Follow your engine manual’s ratio and the oil maker’s label. Mix outdoors in an approved fuel can, away from sparks and flames.
Frequently asked questions
How much oil per gallon at 40:1?
For a 40:1 mix, add 3.2 fl oz (95 ml) of 2-stroke oil to each US gallon of gas, or 25 ml per liter. That is 2.5 % oil.
How much oil for 5 gallons at 40:1?
16 fl oz (473 ml): 5 × 128 = 640 fl oz of gas, and 640 ÷ 40 = 16.
What percent oil is 40:1?
2.5 %: 1 part oil to 40 parts gas, and 1 ÷ 40 = 0.025. Use the ratio your engine’s manual gives.