Ironworkers

Bolt Circle Calculator

Find bolt-hole coordinates and spacing around a bolt circle.

Bolt circle diameter (in) Number of holes Start angle (degrees)

Chord spacing4.592"Radius: 6.000"

Angle step45°

Circumference spacing4.712"

Hole count8

Diameter12.000"

Hole	Angle	X	Y

Coordinates are centerline layout references from the bolt-circle center. Confirm print orientation, datum, and hole size before drilling or burning.

How to use this tool

Bolt Circle Calculator guide

Find bolt-hole coordinates and spacing around a bolt circle. Enter the known field measurements and use the result as a fast estimate or layout reference.

Always verify the print, code requirements, equipment manual, material specification, site conditions, and qualified trade judgment before using calculator results on a real job.