2 Stroke Fuel Mixture Calculator: How Much 2T Oil for Your Petrol
Enter the petrol in litres and the ratio from your engine's manual. See how much two-stroke oil to add, in ml.
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2T oil to add
125ml
- Ratio
- 40 : 1
- Oil in the mix
- 2.44%
- Oil per litre of petrol
- 25 ml
- Total mix
- 5.13 litres
Always use the ratio in your engine's manual. Mix in a clean fuel can away from any flame.
How to use
- Enter how much petrol you are mixing.
- Pick the ratio your engine's manual gives, or enter your own.
- Measure the oil in ml and mix well in a clean can before filling.
Good to know
Oil (ml) = petrol (litres) × 1,000 ÷ ratio. At 40:1, 5 litres of petrol needs 5,000 ÷ 40 = 125 ml of 2T oil; at 50:1 it needs 100 ml; at 25:1 it needs 200 ml.
Ratios differ by engine. Many brush cutters, chainsaws and small water pumps sold in India use 25:1 to 50:1. Older two-stroke scooters and bikes with a separate 2T oil tank mix it automatically — only premix if the manual says so. Always follow the manual.
Use oil made for air-cooled two-stroke engines (2T, JASO FC/FD) unless the manual says otherwise. Too little oil can seize the engine; too much causes smoke and fouled plugs. Mix in a clean, approved fuel can, never near a flame, and use the mix within a few weeks.
Questions
How much 2T oil for 1 litre of petrol?
At 40:1, 25 ml. At 50:1, 20 ml. At 25:1, 40 ml.
What does 40:1 mean?
40 parts petrol to 1 part oil. For every litre of petrol, add 1000 ÷ 40 = 25 ml oil.
Which ratio does my brush cutter need?
Check the manual or the label on the fuel tank. Many use 25:1 or 40:1, but it varies by brand.
I only have 100 ml of oil. How much petrol?
Choose ‘Petrol for my oil’. At 40:1, 100 ml oil goes with 4 litres of petrol.
Is it safe to use more oil than needed?
A little extra is safer than too little, but a lot more causes smoke and carbon build-up. Stick to the manual's ratio.