Always use the mix ratio your equipment manufacturer or oil label specifies.
Oil to add
2.56 US fl oz
75.7 mL
For 1 US gallon of fuel at 50:1
Quick reference
Oil to add for common amounts of fuel, in US fluid ounces and milliliters (rounded).
| Ratio | 1 US gal | 2.5 US gal | 5 US gal |
|---|---|---|---|
| 32:1 | 4.00 oz 118 mL | 10.00 oz 296 mL | 20.00 oz 591 mL |
| 40:1 | 3.20 oz 95 mL | 8.00 oz 237 mL | 16.00 oz 473 mL |
| 50:1 | 2.56 oz 76 mL | 6.40 oz 189 mL | 12.80 oz 379 mL |
| 80:1 | 1.60 oz 47 mL | 4.00 oz 118 mL | 8.00 oz 237 mL |
| 100:1 | 1.28 oz 38 mL | 3.20 oz 95 mL | 6.40 oz 189 mL |
How the math works
A ratio like 50:1 means 50 parts fuel to 1 part oil. A US gallon is 128 fluid ounces, so:
- Oil (US fl oz) = gallons × 128 ÷ ratio. Example: 1 gallon at 50:1 is 128 ÷ 50 = 2.56 fl oz.
- Oil (mL) = liters × 1,000 ÷ ratio. Example: 5 liters at 50:1 is 100 mL.
- 1 US fl oz = 29.5735 mL.
Oil labels often round these numbers. For example, a label may list 2.6 oz per gallon at 50:1. Follow the mixing directions on your oil’s label.
About AMSOIL 2-stroke oil
AMSOIL SABER Professional is a 2-stroke oil for pre-mix equipment, and its label includes a mixing chart. See the SABER Professional section on the small engine page for details from the label, or use AMSOIL’s official lookup guide to see what AMSOIL lists for your equipment.