How the Conduit Size Calculator works
Add each cable type and quantity, choose the permitted fill criterion, and set the largest conduit size the project allows. The calculator evaluates the cable cross-sectional area and returns the smallest single conduit or a minimum-count multi-conduit plan that can carry the entered load.
What the recommendation includes
Results identify the conduit material, trade sizes, conduit count, cable allocation, and calculated fill for every recommended raceway.
Need to verify an existing conduit?
Use the Conduit Fill Calculator to select an installed or specified conduit and check whether its cable load passes.
Conduit sizing questions
What happens when the cable load exceeds one conduit?
The calculator creates a multi-conduit recommendation using the largest permitted trade size where needed and the smallest final size that supplies the remaining capacity.
Can I limit the maximum recommended conduit size?
Yes. Choose the project's maximum allowed trade size in the sizing constraints. Every recommendation will honor that limit.
Can I use manufacturer-specific cable dimensions?
Yes. Select a listed manufacturer and product, or use Custom round cable to enter a project-specific outside diameter.