Bolt Circle Calculator: Calculate Exact Bolt Hole X,Y Coordinates

Calculate Bolt Hole X,Y Coordinates

Enter the diameter of the circle on which the bolt centers lie (e.g., 100mm, 4 inches).
Specify the total number of bolts to be placed on the circle (minimum 2).
Optional: The angle of the first bolt relative to the positive X-axis (default 0°).

Utilize our free online Bolt Circle Calculator to quickly find the exact X and Y coordinates for bolt holes on a pitch circle diameter (PCD) or bolt circle diameter (BCD). Ideal for engineering, machining, and fabrication tasks, ensuring accuracy and saving valuable time for your projects.

Formula:

The Bolt Circle Calculator uses basic trigonometry to determine the X and Y coordinates for each bolt hole on a given bolt circle diameter (BCD).

Let R be the radius (BCD/2).
Let N be the number of bolts.
Let θstart be the starting angle (in degrees).
Let i be the current bolt index (from 0 to N-1).

The angle for each bolt hole (θi) is calculated as:
θi = (i * 360 / N) + θstart (in degrees)

Then, the X and Y coordinates are:
Xi = R * cos(radians(θi))
Yi = R * sin(radians(θi))

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