How Much 2-Stroke Oil for 20 Liters of Gas?
At 50:1, add 400 mL (13.5 fl oz) of 2-stroke oil.
At 40:1, add 500 mL (16.9 fl oz).
At 32:1, add 625 mL (21.1 fl oz).
Not sure which ratio? Use the one in your owner's manual or on the fuel cap. Most modern handheld equipment is 50:1. Other amounts: open the calculator.
Twenty litres is the standard large jerrycan and close to a typical portable outboard tank (6 US gallons is about 22.7 litres). It is a lot of premix for handheld tools, so it is mostly mixed for boats and commercial crews.
Oil for 20 Liters at Every Ratio
| Ratio | Oil (fl oz) | Oil (mL) | Easy measure | Typically used for |
|---|---|---|---|---|
| 50:1 | 13.5 fl oz | 400 mL | about 1.7 cups | Modern chainsaws, trimmers, blowers; most modern outboards |
| 40:1 | 16.9 fl oz | 500 mL | about 2.1 cups | Older equipment, some trimmers and outboards, many dirt bikes |
| 32:1 | 21.1 fl oz | 625 mL | about 2.6 cups | Dirt bikes and motocross, high-load engines |
| 30:1 | 22.5 fl oz | 667 mL | about 2.8 cups | Vintage outboards |
| 25:1 | 27.1 fl oz | 800 mL | about 3.4 cups | Older equipment, break-in when specified |
| 20:1 | 33.8 fl oz | 1000 mL | about 4.2 cups | Vintage engines, some racing |
| 16:1 | 42.3 fl oz | 1250 mL | about 5.3 cups | Antique engines and outboards |
20 liters is 5.28 US gallons. The mL amounts above are exact for any metric ratio: divide the fuel in mL by the ratio (20000 ÷ 50 = 400 mL).
How Precise Do You Need to Be?
Staying within about 10% of the target amount keeps you close to the intended ratio. For 20 liters at 50:1 that means 360–440 mL of oil, and at 40:1, 450–550 mL.
At this batch size, an extra 10 mL of oil turns a 50:1 mix into about 48.8:1, and 10 mL too little makes it about 51.3:1. Running slightly rich (more oil) is safer for the engine than running lean.
Mixed 20 Liters at the Wrong Ratio?
You don't need to throw it out. To correct a full 20-liter batch:
| Situation | Fix |
|---|---|
| Mixed 40:1, need 50:1 | Add 5 liters of fresh gas (25 liters total) |
| Mixed 50:1, need 40:1 | Add 100 mL more oil |
| Mixed 50:1, need 32:1 | Add 225 mL more oil |
| Mixed 32:1, need 50:1 | Add 11.25 liters of fresh gas (31.25 liters total) |
Adding gas makes the batch bigger, so only lean out a mix if you will use the extra fuel within about a month.
How to Mix 20 Liters
- Measure the oil, for example 400 mL (13.5 fl oz) for 50:1. A ratio measuring cup reads directly in ounces and mL.
- Pour the oil into the jerrycan first and add the fuel on top so it mixes as it fills.
- Cap it tightly and shake for about 30 seconds. A fuel can with a sealing cap prevents spills while you shake.
- Write the ratio and date on the can. Shake again before each refill if the can has been sitting.
20 Liters: Common Questions
How much oil for 20 liters of gas at 50:1?
20 liters at 50:1 needs 400 mL (13.5 fl oz) of 2-stroke oil.
How much oil for 20 liters of gas at 40:1?
20 liters at 40:1 needs 500 mL (16.9 fl oz) of 2-stroke oil.
How much oil for 20 liters of gas at 32:1?
20 liters at 32:1 needs 625 mL (21.1 fl oz) of 2-stroke oil.
I mixed 20 liters at 40:1 but my engine needs 50:1. What do I do?
Add 5 liters of fresh gas (25 liters total). That brings the batch back to 50:1 without wasting it.
How long does 20 liters of mixed fuel last?
Mixed 2-stroke fuel without stabilizer is best used within about 30 days. A fuel stabilizer extends that; follow the storage time on the stabilizer's label.
Other Fuel Amounts
Need a ratio guide instead? See 50:1, 40:1, 32:1 or all ratios.