How Much 2-Stroke Oil for 2 Gallons of Gas?
At 50:1, add 5.1 fl oz (151 mL) of 2-stroke oil.
At 40:1, add 6.4 fl oz (189 mL).
At 32:1, add 8 fl oz (237 mL).
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.
Two gallons suits regular weekend use, or running two or three tools from one can. Many 2-gallon cans have no gallon marks, so measure the gasoline at the pump instead of filling the can to the top.
Oil for 2 Gallons at Every Ratio
| Ratio | Oil (fl oz) | Oil (mL) | Easy measure | Typically used for |
|---|---|---|---|---|
| 50:1 | 5.1 fl oz | 151 mL | one 5.2 oz pre-measured 50:1 bottle, or about 10 tablespoons | Modern chainsaws, trimmers, blowers; most modern outboards |
| 40:1 | 6.4 fl oz | 189 mL | about 13 tablespoons | Older equipment, some trimmers and outboards, many dirt bikes |
| 32:1 | 8 fl oz | 237 mL | about 16 tablespoons | Dirt bikes and motocross, high-load engines |
| 30:1 | 8.5 fl oz | 252 mL | about 1.1 cups | Vintage outboards |
| 25:1 | 10.2 fl oz | 303 mL | about 1.3 cups | Older equipment, break-in when specified |
| 20:1 | 12.8 fl oz | 379 mL | about 1.6 cups | Vintage engines, some racing |
| 16:1 | 16 fl oz | 473 mL | exactly 1 pint, or about 2 cups | Antique engines and outboards |
2 gallons is 7.57 liters. These amounts are for US gallons. If your manual uses UK (imperial) gallons, which are about 20% larger, 2 imperial gallons at 50:1 needs 182 mL of oil.
How Precise Do You Need to Be?
Staying within about 10% of the target amount keeps you close to the intended ratio. For 2 gallons at 50:1 that means 4.6–5.6 fl oz of oil, and at 40:1, 5.8–7 fl oz.
At this batch size, an extra 1 fl oz of oil turns a 50:1 mix into about 41.8:1, and 1 fl oz too little makes it about 62.1:1. Running slightly rich (more oil) is safer for the engine than running lean.
Mixed 2 Gallons at the Wrong Ratio?
You don't need to throw it out. To correct a full 2-gallon batch:
| Situation | Fix |
|---|---|
| Mixed 40:1, need 50:1 | Add 0.5 gallons of fresh gas (2.5 gallons total) |
| Mixed 50:1, need 40:1 | Add 1.3 fl oz more oil |
| Mixed 50:1, need 32:1 | Add 2.9 fl oz more oil |
| Mixed 32:1, need 50:1 | Add 1.13 gallons of fresh gas (3.13 gallons 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 2 Gallons
- Measure the oil, for example 5.1 fl oz (151 mL) for 50:1. A ratio measuring cup reads directly in ounces and mL.
- Use a 2-gallon can and leave some room at the top so you can shake the mix.
- 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.
2 Gallons: Common Questions
How much oil for 2 gallons of gas at 50:1?
2 gallons at 50:1 needs 5.1 fl oz (151 mL) of 2-stroke oil.
How much oil for 2 gallons of gas at 40:1?
2 gallons at 40:1 needs 6.4 fl oz (189 mL) of 2-stroke oil.
How much oil for 2 gallons of gas at 32:1?
2 gallons at 32:1 needs 8 fl oz (237 mL) of 2-stroke oil.
I mixed 2 gallons at 40:1 but my engine needs 50:1. What do I do?
Add 0.5 gallons of fresh gas (2.5 gallons total). That brings the batch back to 50:1 without wasting it.
How long does 2 gallons 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.