Bore Stroke Calculator

This calculator helps you determine the engine displacement, piston area, and other important metrics based on bore and stroke dimensions.

Input Parameters

Enter the diameter of the cylinder bore
Enter the distance the piston travels up and down
Enter engine compression ratio (optional)

Calculation Results

Calculation Formula

Engine Displacement = π × (bore/2)² × stroke × number of cylinders

Where:
π = 3.14159
bore = cylinder diameter
stroke = piston travel distance
number of cylinders = engine configuration factor

Piston Area:

-

Engine Displacement:

-

Cylinder Volume:

-

Bore Stroke Calculator Calculator Usage Guide

Learn how to use the Bore Stroke Calculator and understand its working principles

How to Use the Calculator

  1. Enter the bore measurement (cylinder diameter) in either inches or millimeters
  2. Enter the stroke measurement (piston travel distance) in the same unit as the bore
  3. Optionally, enter the compression ratio if you want to calculate it
  4. Click the "Calculate" button to compute the results
  5. Use the "Reset" button to clear all inputs and start over

Understanding the Results

  • Piston Area: The area of the piston head in square millimeters
  • Engine Displacement: The total volume displaced by all pistons in cubic centimeters (cc)
  • Cylinder Volume: The volume of a single cylinder in cubic centimeters
  • Compression Ratio: The ratio of the volume above the piston at the bottom of the stroke to the volume above the piston at the top of the stroke

Formula Explanations

The calculator uses these formulas:

Piston Area = π × (bore/2)²

Engine Displacement = Piston Area × stroke × number of cylinders

Compression Ratio = (Volume at Bottom Dead Center) / (Volume at Top Dead Center)

Example

If you have an engine with a bore of 4.000 inches and a stroke of 3.500 inches:

1. Enter 4.000 in the bore field and 3.500 in the stroke field

2. Select "Imperial" as the unit

3. Click "Calculate"

4. The calculator will display the piston area, engine displacement, and other metrics