About the Bolt Pattern Calculator
Bolt circle diameter, hole spacing and X-Y coordinates for a circular bolt pattern.
Also known as: bolt circle calculator, pcd calculator, wheel bolt pattern, hole circle coordinates.
How to use this calculator
- Enter number of bolts, bolt circle diameter, start angle.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
chord = 2R·sin(180°/n)
Worked example
Using the values pre-filled in the calculator above:
- Number of bolts = 6
- Bolt circle diameter = 120 mm
- Start angle = 0 °
the calculator returns:
- Chord between adjacent holes: 60 mm
- Angle between holes: 60 °
- Bolt circle radius: 60 mm
- Arc length between holes: 62.8319 mm