Home Ratios 25:1 Mix Ratio

25:1 Mix Ratio Calculator & Chart

Quick Answer A 25:1 mix ratio means 25 parts gasoline to 1 part 2-stroke oil. For 1 gallon of gas, you need 5.1 fl oz (151 mL) of oil. This ratio is used by older equipment and engines requiring richer oil mixture.

25:1 Mix Calculator

25:1

Fixed ratio for this calculator

Oil Needed

You Need
5.1
fl oz
for 1 gallon at 25:1 ratio
Milliliters
151
US Fluid Ounces
5.1
Liters
0.151

Need a different ratio? Use our full calculator →

What is a 25:1 Mix Ratio?

A 25:1 mix ratio means you mix 25 parts gasoline with 1 part 2-stroke oil. This creates a fuel mixture that is 3.85% oil and 96.15% gasoline by volume.

The 25:1 ratio is used by older equipment and engines requiring richer oil mixture.

The 25:1 ratio equals approximately 5.1 fl oz (151 mL) of oil per gallon of gasoline, or about 40 mL per liter.

Complete 25:1 Mixing Chart

Use this chart for quick reference when mixing fuel at 25:1 ratio:

US Gallons

Fuel (Gallons) Oil (fl oz) Oil (mL) Oil (Liters)
1 gallon 5.1 fl oz 151 mL 0.151 L
2 gallons 10.2 fl oz 302 mL 0.302 L
2.5 gallons 12.8 fl oz 378 mL 0.378 L
3 gallons 15.3 fl oz 453 mL 0.453 L
4 gallons 20.4 fl oz 604 mL 0.604 L
5 gallons 25.5 fl oz 755 mL 0.755 L
6 gallons 30.6 fl oz 906 mL 0.906 L
10 gallons 51.0 fl oz 1510 mL 1.510 L

Liters

Fuel (Liters) Oil (mL) Oil (fl oz)
1 liter 40 mL 1.35 fl oz
2 liters 80 mL 2.71 fl oz
5 liters 200 mL 6.76 fl oz
10 liters 400 mL 13.53 fl oz
20 liters 800 mL 27.05 fl oz

Equipment That Uses 25:1 Ratio

The 25:1 ratio is used by older equipment and engines requiring richer oil mixture:

Vintage Chainsaws

Older chainsaw models from the 1970s and 1980s.

Break-In Period

Some manufacturers recommend 25:1 during engine break-in.

High-Performance Racing

Racing 2-stroke engines under extreme loads.

Older Outboards

Vintage outboard motors from the 1970s and earlier.

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 →

25:1 Ratio FAQs

How much oil for 1 gallon at 25:1?
For 1 gallon of gasoline at 25:1 ratio, you need 5.1 fl oz (151 mL) of 2-stroke oil.
What equipment uses 25:1 ratio?
The 25:1 ratio is used by older equipment and engines requiring richer oil mixture.
Is 25:1 the same as 3.85%?
Yes, a 25:1 ratio equals 3.85% oil by volume. This means 3.85% of your total fuel mixture is 2-stroke oil and 96.15% is gasoline.
How do I mix 25:1 fuel?
To mix 25:1 fuel:
  1. Pour desired amount of gasoline into an approved fuel container
  2. Measure 5.1 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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