Conduit Fill Calculator
Calculate wire fill percentage for NEC compliance. Maximum 40% fill for conduits with more than 2 wires.
Quick Presets
Conduit Type & Size
Wire Configuration
Fill Calculation
11.5%
NEC Compliant
Total Wire Area
0.0399 in²
Conduit Area
0.3460 in²
Max Fill (40%)
0.1380 in²
Available Space
0.0981 in²
Maximum Wire Count
12 AWG THHN/THWN
Hot, neutral, ground
10 max
in this conduit
NEC Guidelines
Article 314.16: Conduit fill limitations
• 1 wire: 53% max fill
• 2 wires: 31% max fill
• 3+ wires: 40% max fill
⚠️ This calculator is for reference only. Always verify with local AHJ and current NEC requirements.