Fill out the form and click "Calculate Fill" to see results
How to Use the Calculator
- Select your conduit type and trade size
- Choose wire type and gauge (AWG)
- Enter the number of conductors
- The calculator will determine if the configuration is NEC compliant
| Number of Conductors |
Max Fill (%) |
| 1 |
53% |
| 2 |
31% |
| 3 or more |
40% |
- Always consult the latest NEC for field compliance
- Leave room for future wire additions when planning conduit runs
- Consider heat dissipation when running multiple current-carrying conductors
- Remember to account for derating when conduit fill exceeds 30%
Note: This calculator is for educational and planning purposes. Always consult the latest NEC (National Electrical Code) for field compliance.
Sample Conduit Fill Configurations
| Conduit |
Size |
Wire Type |
Gauge |
Qty |
Fill (%) |
Status |
| EMT |
3/4" |
THHN |
12 AWG |
9 |
38.2% |
OK |
| EMT |
1" |
THHN |
10 AWG |
12 |
42.5% |
Near |
| PVC |
1/2" |
NM-B |
14 AWG |
5 |
58.3% |
Over |
| RMC |
1 1/2" |
XHHW |
8 AWG |
15 |
36.8% |
OK |
| FMC |
3/4" |
THHN |
12 AWG |
7 |
29.7% |
OK |