Two-Stroke Premix Ratio Calculator
and Quick Reference Table
My head is not a calculator...
At least, it isn't a reliable calculator.
It is kinda like a solar calculator on a cloudy day... In the shade.
So, I like to devise ways to not need a calculator when calculation situations arise in my life. Situations like...
Needing to convert the number of ounces of oil to add to an odd number of gallons of fuel to get a particular fuel-to-oil ratio. In some cases, the brain is provided only with a fuel-to-oil percentage (%), which then needs to be converted to a ratio! This places further demands on my low-light operating conditions.
So, if you are like me and premix gas ratios for your two stroke engine can get a little confusing, even in bright sunlight... Here are a couple handy tools to make sure you get accurate mixing ratios every time.
For reference:
- 1960 Lambretta TV175 = 20:1 oil/fuel ratio = 5%
- SAAB 3-cyl premix = ??:1 oil/fuel ratio = ?%
Calculator + / or Table
Premix Calculator
To calculate how much oil to add to your gasoline:
- Type the number of gallons (or liters) of fuel you are using in the first box.
- Adjust the ratio desired in the second box.
- Hit your Enter key.
The calculated amount of Two-Cycle Oil to use will be displayed in the final box.
Premix Quick Reference Table
| Ratio = Percent | ||||
| 17:1 = 6% | ||||
| 20:1 = 5% | ||||
| 25:1 = 4% | ||||
| 32:1 = 3% | ||||
| 50:1 = 2% | ||||
| Gallons of fuel to Ounces of oil | ||||||||||
| Ratio Gas:Oil |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| 17:1 | 7.5 | 15.1 | 22.6 | 30.1 | 37.6 | 45.2 | 52.7 | 60.2 | 67.8 | 75.3 |
| 20:1 | 6.4 | 12.8 | 19.2 | 25.6 | 32.0 | 38.4 | 44.8 | 51.2 | 57.6 | 64.0 |
| 25:1 | 5.1 | 10.2 | 15.4 | 20.5 | 25.6 | 30.7 | 35.8 | 41.0 | 46.1 | 51.2 |
| 32:1 | 4.0 | 8.0 | 12.0 | 16.0 | 20.0 | 24.0 | 28.0 | 32.0 | 36.0 | 40.0 |
| 50:1 | 2.6 | 5.1 | 7.7 | 10.2 | 12.8 | 15.4 | 17.9 | 20.5 | 23.0 | 25.6 |
| Gallons of fuel to Ounces of oil | ||||||||||
| Ratio Gas:Oil |
11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| 17:1 | 82.8 | 90.4 | 97.9 | 105.4 | 112.9 | 120.5 | 128.0 | 135.5 | 143.1 | 150.6 |
| 20:1 | 70.4 | 76.8 | 83.2 | 89.6 | 96.0 | 102.4 | 108.8 | 115.2 | 121.6 | 128.0 |
| 25:1 | 56.3 | 61.4 | 66.6 | 71.7 | 76.8 | 81.9 | 87.0 | 92.2 | 97.3 | 102.4 |
| 32:1 | 44.0 | 48.0 | 52.0 | 56.0 | 60.0 | 64.0 | 68.0 | 72.0 | 76.0 | 80.0 |
| 50:1 | 28.2 | 30.7 | 33.3 | 35.8 | 38.4 | 41.0 | 43.5 | 46.1 | 48.6 | 51.2 |
Finally, here is the same quick reference table in MS Excel format.