The relationship
Formula
xᵢ = cx + R cos(α + 2πi÷n) · yᵢ = cy + R sin(α + 2πi÷n)
For PCD 100 mm, 4 holes, start angle 0° and center (0,0): the first points are (50,0), (0,50), (−50,0), (0,−50).
Workshop layout
Bolt Circle & PCD Coordinate Calculator
Lay out equally spaced holes without drawing the circle first. Set the pitch circle diameter, hole count, start angle and center to produce a workshop-ready coordinate table.
FreeNo sign-inInstant results
INPUT
Define the bolt circle
Coordinates update in hole order.
ADJACENT HOLE SPACING70.7107 mm
| Hole | Angle | X (mm) | Y (mm) |
|---|---|---|---|
| 01 | 0° | 50 | 0 |
| 02 | 90° | 0 | 50 |
| 03 | 180° | -50 | 0 |
| 04 | 270° | -0 | -50 |
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Common questions
What does PCD mean?
PCD means pitch circle diameter: the diameter of the imaginary circle passing through the centers of all bolt holes.
How does the start angle change coordinates?
It rotates every hole around the same center while preserving the PCD and equal spacing.
Where is the X/Y origin?
The origin is the center coordinate you enter. The default center is X 0, Y 0.
How do I calculate distance between adjacent holes?
For equally spaced holes, adjacent center distance is PCD × sin(π ÷ hole count). The calculator shows it automatically.