Circumference Calculator (by Diameter)
Calculate circumference directly from diameter without manual division. Ideal for engineering, pipe fitting, and fabrication. Supports mm, cm, m, in, ft.
About
Fabricators, machinists, and engineers often work with diameter rather than radius. Measuring the total width across a circular object is more practical than finding a theoretical center point. This calculator eliminates the intermediate step of dividing by two. It computes the total perimeter distance directly from the diameter input.
Precision is vital in trades like pipe fitting or tank construction. A small error in diameter measurement scales up by a factor of Pi (π) in the final circumference. This tool allows for rapid unit switching. You can input a diameter in inches and instantly receive the circumference in feet or millimeters. This feature streamlines material ordering and fabrication layout tasks.
Formulas
The relationship between diameter and circumference is linear and defined by the irrational constant Pi.
Circumference Formula:
C = π ⋅ d
Where π ≈ 3.14159
If you only have the radius r, the diameter is simply 2r.
Reference Data
| NPS (Pipe Size) | Actual Diameter (OD) | Circumference |
|---|---|---|
| 1 inch | 1.315 in | 4.13 in |
| 2 inch | 2.375 in | 7.46 in |
| 3 inch | 3.500 in | 10.99 in |
| 4 inch | 4.500 in | 14.13 in |
| 6 inch | 6.625 in | 20.81 in |
| 8 inch | 8.625 in | 27.09 in |
| 10 inch | 10.750 in | 33.77 in |
| 12 inch | 12.750 in | 40.05 in |