Mixing fuel for a 2-stroke engine is not particularly complicated.
At least, it should not be.
You have a quantity of fuel, a required fuel-to-oil ratio, and an amount of 2-stroke oil that needs to be added. The calculation itself is straightforward, but it becomes surprisingly easy to second-guess when you are standing beside a mower, chainsaw, brushcutter, blower or another piece of equipment with a fuel container in front of you.
Was that 25:1 or 40:1?
How much oil is needed for this amount of fuel?
Was the measurement calculated using litres, US gallons or UK gallons?
Rather than repeatedly looking up conversion tables or reaching for a calculator, I created the Jays n Dees 2-Stroke Fuel Mix Calculator.
What the Calculator Does
The calculator works out how much 2-stroke oil is required for a selected amount of fuel and fuel-to-oil ratio.
You choose:
- the unit used to measure the fuel
- the required mixing ratio
- the amount of fuel being prepared
The calculator then displays the corresponding oil quantity.
It supports:
- litres
- US gallons
- UK gallons
- common fuel-to-oil ratios
- custom ratios
- preset fuel quantities
- custom fuel quantities
This means it can be used with a range of equipment and measuring systems without manually converting everything first.
Why the Different Gallon Types Matter
One reason fuel calculations can become confusing is that a gallon is not always the same quantity.
A US gallon and a UK imperial gallon are different sizes. Using the wrong gallon measurement can therefore produce the wrong oil quantity, even when the mixing ratio itself is correct.
The calculator treats litres, US gallons and UK gallons as separate units.
Where possible, it uses the browser region to select a likely starting unit, but that selection can be changed at any time. There is also a Cycle Unit button for quickly moving between the available measurement systems.
Common and Custom Mixing Ratios
Many pieces of 2-stroke equipment use familiar ratios such as 25:1, 40:1 or 50:1.
The calculator provides common ratio choices for convenience, but it is not limited to those options. A custom ratio can be entered when a particular engine or manufacturer specifies something different.
For example, entering 25 represents a fuel-to-oil ratio of 25:1.
This flexibility is useful because not every 2-stroke engine uses the same mixture. Older equipment, newer equipment and specialised engines may all have different requirements.
The calculator does not attempt to decide which ratio your equipment needs. That information must come from the equipment manufacturer, instruction manual or another reliable specification for the engine.
Its job is to calculate the oil quantity after you provide the correct ratio.
Saving Frequently Used Mixtures
Most people who regularly use 2-stroke equipment tend to prepare the same few mixtures repeatedly.
You may always mix:
- the same fuel quantity
- in the same unit
- at the same ratio
The calculator allows useful combinations to be saved as favourites for quicker reuse.
These favourites are stored locally on the device rather than being attached to an online account. This keeps the feature simple and avoids requiring registration merely to save a common calculation.
Once saved, a favourite can be selected again without rebuilding the mixture from the beginning.
Available Online and Offline
The calculator is built as an installable Progressive Web App, commonly shortened to PWA.
That means it can be opened through a web browser and, on supported devices and browsers, installed for more app-like access. It is also designed to remain available offline after it has been loaded and installed correctly.
Offline access is particularly useful for this kind of tool.
Two-stroke equipment is often used in sheds, gardens, paddocks, workshops and other places where an internet connection may be weak or unavailable. A calculator that stops working when the connection disappears would be far less useful.
The saved favourites also remain on the device for convenient reuse.
A Small Tool for a Specific Job
The 2-Stroke Fuel Mix Calculator is deliberately focused.
It is not an equipment-management platform, maintenance tracker or complicated workshop system. It does not require an account, and it does not try to recommend a mixing ratio without knowing the engine involved.
It performs one practical job:
It calculates the amount of 2-stroke oil required for the fuel quantity and ratio you select.
Sometimes that is all a tool needs to do.
Always Check the Manufacturer’s Requirements
The calculator is provided as a mixing guide.
Always confirm the correct fuel type, oil type and fuel-to-oil ratio specified by the engine or equipment manufacturer before preparing a mixture.
Using the wrong ratio or unsuitable oil may affect performance or damage equipment. If the instructions printed on the equipment differ from information found elsewhere, follow the applicable manufacturer documentation.
Once the correct ratio is known, the calculator can take care of the maths behind it.
Try the Free Calculator
The Jays n Dees 2-Stroke Fuel Mix Calculator is available free through the Jays n Dees website.
Open the 2-Stroke Fuel Mix Calculator
Choose the fuel unit, select or enter the required ratio, enter the amount of fuel, and the calculator will show how much oil to add.
Save the combinations you use regularly, and the next mixture should take only a few moments to calculate.