Low-Voltage Conduit Fill Calculator (%)

How many Cat 6 cables fit in 1-inch conduit?

It depends on the conduit type, because Table 4 internal area differs between EMT, PVC, and others. This calculator sums each cable's area using π/4 × OD² (Cat 6 is taken at a 0.25-inch finished OD) and compares the total to the NEC Chapter 9 Table 1 allowance — 40% for the common multi-cable case. Enter your conduit and quantities to get the exact pass/fail and the smallest size that fits.

Related questions

• What is the conduit fill limit for low-voltage cable?
• Why are low-voltage cables sized by outer diameter?