Custom flange calculator: bolt hole coordinates, drawing and weight
Enter the dimensions of a non-standard flange to get bolt hole coordinates, a scaled drawing, the weight and a DXF file for CNC/CAD instantly. Turn your flange into a quote request with one click; we manufacture up to DN 3000 at our factory in Istanbul and export to 37+ countries.
Flange dimensions
Weight is the theoretical net weight of a plate flange (raised face and hub not included). Actual weight varies with manufacturing tolerances.
Result
Bolt hole coordinates
| Hole | Angle (°) | X (mm) | Y (mm) |
|---|
The origin (0, 0) is the flange centre. Angles are measured counter-clockwise from the +X axis; hole numbers match the drawing.
Drawing ready? We will make it.
Custom flanges up to DN 3000, plasma cut and CNC turned. EN 10204 3.1 certificates on request. Exporting to 37+ countries since 1998.
How are bolt hole coordinates calculated?
Bolt holes are equally spaced on the bolt circle diameter (PCD). On a flange with n holes, the angle between two holes is 360/n degrees.
Each hole is at X = (PCD/2) · cos α, Y = (PCD/2) · sin α. On standard flanges the first hole is offset by 180/n degrees so the holes straddle the vertical and horizontal centrelines and no hole sits on an axis.
How is flange weight calculated?
Take the area of the outside diameter, subtract the bore and all bolt holes, and multiply by the thickness to get the volume. Volume × density = weight.
Carbon steel is 7.85 g/cm³ and stainless 304 is 7.93 g/cm³. For standard EN 1092-1, ASME B16.5 and JIS flanges, ask us for catalogue weights.
What do the ligament warnings mean?
If too little material is left between two holes or between a hole and the edge, the flange can deform during cutting and drilling and may not carry the bolt load safely.
The calculator flags these cases. Final design must follow the applicable standard and specification; if in doubt, ask our engineers.