Conduit Fill Calculator
Add your conductors, pick a conduit size, and see instantly whether the pull is legal — or what size it needs to be.
Conductors in the raceway (THHN/THWN-2)
Conductor area
0.0399 in²
Fill (40% allowed)
7.5%
Allowed area
0.2132 in²
✅ 3 conductors fit in 3/4" EMT.
Based on NEC Chapter 9 Tables 1, 4, and 5 (EMT, THHN/THWN-2). Fill limits: 1 conductor 53%, 2 conductors 31%, 3+ conductors 40%. Verify against the current code edition — and remember the 360° bend rule and pulling tension are separate questions.
The rules behind it
NEC Chapter 9, Table 1 limits raceway fill to 53% for one conductor, 31% for two, and 40% for three or more. This calculator uses THHN/THWN-2 areas from Table 5 and EMT internal areas from Table 4. Other insulation types and raceways (RMC, PVC, ENT) have different areas — support for those is coming.
Remember: fill is only one constraint. Keep total bends under 360° between pull points, and long or heavy pulls deserve a pulling-tension check.