Anchor bolt / bolt circle layout calculator
Enter bolt count and bolt circle diameter to generate an evenly spaced X/Y coordinate table and diagram - keep it open on the screen while you lay out a base plate or column anchor pattern.
Formula & assumptions
Angle step = 360° / N. Chord spacing = BCD × sin(180°/N). Coordinates from the pattern center (0,0), or from your center offset if entered: X = offset_X + (BCD/2)·cos(θ), Y = offset_Y + (BCD/2)·sin(θ), where θ = start angle + rotation + i·(360°/N) for bolt i = 0..N-1. Bolts are assumed evenly spaced around the circle - uneven/custom patterns are not covered.
Layout aid only - not anchor, concrete, or connection design. Anchor rod size, embedment, edge distance, projection, and base plate/pier design come from the project structural drawings, EOR, and applicable code (e.g. ACI 318 Chapter 17) - verify before laying out or drilling.