This is a collection of calculators that may be helpful to scooter enthusiasts.

CLICK HERE if you need to do a unit conversion.

Fuel/Oil Mix Ratio Calculator

Enter the amount of fuel and the desired mix ratio(__:1) and this calculator will tell you the amount of oil needed in both ounces and milliliters.

Gallons of Fuel Ounces of Oil
Desired Mix Ratio Milliliters of Oil
Homemade Octane Booster Caclulator

This calculator can help you make homemade octane booster from a number of chemicals. If you enter the gallons of mixed fuel you wish to make, the octane of the gasoline you will be using, choose and additive, and enter the percentage of the additive that you wish to use this calculator will tell you how much gasoline, selected additve (in either oz or gal), cleaning agent (such as mineral spirits), and lubricating agent (such as transmission fluid) is needed as well as an approximate octane rating of the mixture. The octane rating is likely to be off by a small margin, but it should be a close estimate. You need to research mixture levels and adverse effects of these chemicals. Some of these chemicals can be harmful to fuel lines, sensors, and more. Most are not safe at levels of 30% or higher, some much less. Do your research before deciding to make your own octane booster. This calculator is just here to help anyone that is mixing their own fuel.

Gallons of Fuel Desired
Gasoline (gal)
Octane of Gasoline
Additive (oz)
Additive (gal)
Percent of Additive
Cleaning Agent (oz)
Lubricating Agent (oz)
Mixed Octane
Fuel/Oil Economy Calculator

If you enter all the required fields, this calculator can tell you the fuel economy, fuel cost, oil cost for 2 strokes, and cost per mile for fuel and oil. If you are using this calculator for a 4 stroke you can leave the oil fields blank.

Miles Traveled
Fuel Cost (Trip)
Gallons of Fuel Used
Oil Cost (Trip)
Fuel Cost Per Gallon
Fuel Cost Per Mile
Oil Mix Ratio Oil Cost Per Mile
Oil Cost Per Quart Total Cost Per Mile
Tire Diameter And Circumference

Enter the tire width(mm), aspect ratio, and wheel diameter(in) and this calculator will tell you the tire's diameter and circumference in inches and millimeters. Circumference in mm is often used to calibrate aftermarket speedometers.

Width(mm) Aspect Ratio Wheel Diameter(in)
Width Diameter (in)
Aspect Ratio Diamter (mm)
Wheel Diameter Circumference (in)
Circumference (mm)
Speed Calculator

Enter tire circumference(in), final drive ratio(__:1), and engine RPM and this calculator will give you the maximum speed for that setup. This may be a bit inaccurate for CVT driven scooters. You would actually need to know the RPM that the clutch bell is turning to be completely accurate. This calculator can give you a good idea of max speed differences using different tire sizes, different gear ratios, or setups that rev a little different.

Tire Circumference
Final Drive Ratio Speed
Speedometer Tire Size Correction Calculator

This calculator can help you improve the accuracy of speedometers that require a tire size input for calibration. Enter the current tire size in your gauge (usually circumference in mm). Then you will need to have a trip odometer reading from a ride as well as a known accurate mileage from the same ride (usually GPS info) to enter. The calculator will output a corrected tire size for the gauge based on your inputs.

Current Tire Size
Speedometer Mileage Corrected Tire Size
Actual Mileage
Displacement Calculator

Enter the bore and stroke in millimeters and the number of cylinders and this calculator will tell you the displacement in both cubic centimeters and cubic inches.

Displacement (cc)
Displacement (ci)
# of Cylinders
Piston Ring End Gap Calculator

Enter the bore in millimeters and this calculator will tell you the compression ring end gaps in inches for two-stroke and four-stroke engines.

4T Top Ring

4T Second
2T Rings

Compression Ratio Calculator

Enter the volume of the cylinder and the volume of the combustion chamber and this calculator will tell you the compression ratio (referred to as secondary compression in 2 strokes). For multi-cylinder engines, just use the columes from one cylinder. If you wish to find the effective (corrected) compression ratio of a 2 stroke engine, enter the effective cylinder volume instead of the total cylinder volume. Don't forget to add the volume of the cylinder head gasket to the volume of the combustion chamber. You can find the head gasket's volume by using the displacement calculator above (enter the gasket's thickness in mm into the stroke field). You also need to take deck height and the piston (dished, flat, or domed) into account.

Cylinder Volume
Compression Ratio
Combustion Chamber Volume
Combustion Chamber Volume

This calculator will tell you the combustion chamber volume necessary to achieve your desired compression ratio (__:1). If you are using a head gasket, remember that it's volume needs to be subtracted from the combustion chamber volume shown here to get a correct result.

Desired Compression Ratio
Combustion Chamber Volume
Cylinder Volume
Primary Compression Ratio

Enter the crankcase volume(cc) and cylinder volume(cc) and this calculator will show you the primary compression ratio of a 2 stroke engine.

Crankcase Volume
Primary Compression
Cylinder Volume
1/4 Mile Calculator

Enter 1/4 mile elapsed time (E.T.) in seconds and trap speed along with the vehicle weight with driver (lb) and this calculator will give you an estimate of horsepower and torqe to the wheel(s) as well as power to weight ratio (HP per lb).

1/4 Mile E.T. Horsepower (E.T. Method)
1/4 Mile Trap Speed Torque (E.T. Method)
Vehicle Weight Horsepower (Trap Method)
Engine RPM (Trap) Torque (Trap Method)
Horsepwer (Average of ET and Trap Methods)
Torque (Average of ET and Trap Mehods)
Power To Weight Ratio (Average)