Use this calculator to work out how much two-stroke oil to add to a measured quantity of fuel for a selected premix ratio.
It is suitable for modern premix two-stroke motocross motorcycles. Always use the ratio specified for your motorcycle, engine setup and oil product.
| Ratio | Oil Required Per Litre of Fuel |
|---|---|
| 20:1 | 50 ml per litre |
| 25:1 | 40 ml per litre |
| 32:1 | 31.25 ml per litre |
| 40:1 | 25 ml per litre |
| 50:1 | 20 ml per litre |
Important: These ratios are calculation references only. They are not recommendations for a particular motorcycle.
| Fuel | 25:1 | 32:1 | 40:1 | 50:1 |
|---|---|---|---|---|
| 5 Litres | 200 ml | 156 ml | 125 ml | 100 ml |
| 10 Litres | 400 ml | 313 ml | 250 ml | 200 ml |
| 20 Litres | 800 ml | 625 ml | 500 ml | 400 ml |
A premix ratio describes the amount of fuel compared with one part of two-stroke oil.
For example, a 40:1 ratio means 40 parts fuel to one part oil.
The calculator converts the entered fuel quantity into millilitres and divides it by the selected ratio.
Use the premix ratio specified by the motorcycle manufacturer, engine builder or two-stroke oil manufacturer where applicable.
The correct ratio can depend on the motorcycle, engine configuration, operating conditions and lubricant being used.
Do not change the premix ratio simply to correct jetting or fuel-injection problems.
Measure the fuel and oil accurately using clean equipment.
Mix the oil thoroughly through the fuel before filling the motorcycle.
Avoid allowing dirt, water or other contamination into the fuel container or motorcycle fuel system.