Electrical Calculators
Conduit Fill
Plan raceway fill with a transparent, verification-first workflow.
01
Inputs
02
Result & worksheet
15.83% fill — within entered limit
Recorded summary
- Conductors: 4
- Occupied area: 0.0844 in²
- Raceway area: 0.533 in²
- Entered limit: 40%
- Margin: 0.1288 in²
Formula used
Fill % = (quantity × conductor area ÷ raceway internal area) × 100Calculation steps
- 4 × 0.0211 in² = 0.0844 in² occupied
- (0.0844 ÷ 0.533) × 100 = 15.83%
- Entered allowable area: 0.2132 in²
Assumptions
- All entered conductors use the same table area
- Raceway and conductor areas use the same square units
- The user-entered allowable percentage matches the conductor count and adopted edition
Verify before use
- NEC Chapter 9, Table 1 for allowable percentage
- Applicable Chapter 9 Table 4 raceway dimensions
- Applicable Chapter 9 Table 5 or 5A conductor dimensions
- Notes, nipples, multiconductor cables, and local amendments
- Ampacity adjustment is a separate check