Home Ratios 20:1 Mix Ratio

20:1 Mix Ratio Calculator & Chart

Quick Answer A 20:1 mix ratio means 20 parts gasoline to 1 part 2-stroke oil. For 1 gallon of gas, you need 6.4 fl oz (189 mL) of oil. This ratio is very rich mixture for vintage equipment and severe-duty applications.

20:1 Mix Calculator

20:1

Fixed ratio for this calculator

Oil Needed

You Need
6.4
fl oz
for 1 gallon at 20:1 ratio
Milliliters
189
US Fluid Ounces
6.4
Liters
0.189

Need a different ratio? Use our full calculator →

What is a 20:1 Mix Ratio?

A 20:1 mix ratio means you mix 20 parts gasoline with 1 part 2-stroke oil. This creates a fuel mixture that is 4.76% oil and 95.24% gasoline by volume.

The 20:1 ratio is very rich mixture for vintage equipment and severe-duty applications.

The 20:1 ratio equals approximately 6.4 fl oz (189 mL) of oil per gallon of gasoline, or about 50 mL per liter.

Complete 20:1 Mixing Chart

Use this chart for quick reference when mixing fuel at 20:1 ratio:

US Gallons

Fuel (Gallons) Oil (fl oz) Oil (mL) Oil (Liters)
1 gallon 6.4 fl oz 189 mL 0.189 L
2 gallons 12.8 fl oz 378 mL 0.378 L
2.5 gallons 16.0 fl oz 473 mL 0.472 L
3 gallons 19.2 fl oz 567 mL 0.567 L
4 gallons 25.6 fl oz 756 mL 0.756 L
5 gallons 32.0 fl oz 945 mL 0.945 L
6 gallons 38.4 fl oz 1134 mL 1.134 L
10 gallons 64.0 fl oz 1890 mL 1.890 L

Liters

Fuel (Liters) Oil (mL) Oil (fl oz)
1 liter 50 mL 1.69 fl oz
2 liters 100 mL 3.38 fl oz
5 liters 250 mL 8.45 fl oz
10 liters 500 mL 16.91 fl oz
20 liters 1000 mL 33.81 fl oz

Equipment That Uses 20:1 Ratio

The 20:1 ratio is very rich mixture for vintage equipment and severe-duty applications:

Very Old Equipment

Equipment from the 1960s and 1970s with older oil technology requirements.

Break-In (Racing)

Initial break-in for high-performance racing engines.

Severe Duty

Engines operating under extreme conditions or heavy loads.

Vintage Outboards

Very old outboard motors (pre-1970).

Always Use Your Equipment's Recommended Ratio

Using the wrong ratio can damage your engine. Check your owner's manual for the correct ratio.

Compare ratios →

20:1 Ratio FAQs

How much oil for 1 gallon at 20:1?
For 1 gallon of gasoline at 20:1 ratio, you need 6.4 fl oz (189 mL) of 2-stroke oil.
What equipment uses 20:1 ratio?
The 20:1 ratio is very rich mixture for vintage equipment and severe-duty applications.
Is 20:1 the same as 4.76%?
Yes, a 20:1 ratio equals 4.76% oil by volume. This means 4.76% of your total fuel mixture is 2-stroke oil and 95.24% is gasoline.
How do I mix 20:1 fuel?
To mix 20:1 fuel:
  1. Pour desired amount of gasoline into an approved fuel container
  2. Measure 6.4 fl oz of 2-stroke oil per gallon (use chart above)
  3. Add oil to gasoline (not the other way around)
  4. Cap the container and shake for 30 seconds to mix thoroughly
  5. Use within 30 days for best results
View detailed mixing guide →

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