Roll Outside Diameter Calculator
Roll Outside Diameter Calculator: calculate od² with consistent units and explicit assumptions.
Inputs
mm
m
µm
Results
- Outside diameter
- 271.407401 mm
- Core diameter
- 100 mm
- Thickness
- 50 µm
- Turns
- 1,714.074009 turns
- Length
- 1,000 m
Formula
OD² = core² + 4 × thickness × length ÷ π
Turns = (OD−core) ÷ (2 × thickness)
Length = π × turns × (core + thickness × turns)
Assumptions & limits
- Ideal tight winding, constant effective ply thickness; no entrapped air.
Worked example
For the example inputs: Outside diameter = 271.4074 mm; Core diameter = 100 mm; Thickness = 50 µm.
OD² = core² + 4 × thickness × length ÷ π