Center Distance Calculator (Spur Gears)
This calculator is valid for standard spur gears only.
Formula:
a = m × (z₁ + z₂) / 2
These calculators are intended as quick reference tools only. Results are approximate and should not replace professional engineering judgment, calculations, or validation.
Center Distance Calculator (Spur Gears)

This page provides a center distance calculator for spur gears.
The tool helps calculate the center distance between two meshing spur gears.
All calculations use the metric system.
Purpose of the Calculator
The calculator determines the center distance from the gear module and the number of teeth on each gear.
It also calculates the pitch diameter of both gears.
The tool is intended for standard spur gears with parallel shafts.
Typical Applications
Center distance is an important parameter in spur gear design.
It defines the position of the gear shafts and affects proper gear meshing.
This calculator is useful for gearbox design, machine design, technical calculations, and engineering education.
Calculation Method
The calculator uses standard metric gear formulas.
Formula:
Center Distance (a) = m × (z₁ + z₂) / 2
where:
- a = Center Distance (mm)
- m = Module (mm)
- z₁ = Number of Teeth of Gear 1
- z₂ = Number of Teeth of Gear 2
The pitch diameters are calculated as:
- D₁ = m × z₁
- D₂ = m × z₂
All dimensions are displayed in millimeters (mm).
Usage Notes
The calculator runs directly in your web browser.
No installation or registration is required.
It works on desktop computers, tablets, and mobile devices.
Results are displayed instantly after entering the required values.
Disclaimer
This calculator is provided for informational purposes only.
Always verify the results before using them in engineering design, manufacturing, or safety-critical applications.
We do not accept responsibility for decisions based on these calculations.
