Conduit Fill Area Reference Tables
Internal conduit areas and percentage-based available areas generated from the same verified dimensional dataset used by the calculator.
How to use these tables
Values are shown in square inches. Multiply cable outside-area by quantity, then compare that occupied area with the appropriate available fill area. Use the project’s governing fill criterion; 40% is the calculator’s default low-voltage planning value.
EMT conduit fill areas
Dimensional source: Wheatland Tube, EMT & Conduit brochure. Verify the exact manufacturer product and project requirements before use.
| Trade size | Inside diameter | Internal area | 30% area | 31% area | 40% area | 53% area |
|---|---|---|---|---|---|---|
| 1/2" | 0.622 in | 0.304 in² | 0.091 in² | 0.094 in² | 0.122 in² | 0.161 in² |
| 3/4" | 0.824 in | 0.533 in² | 0.160 in² | 0.165 in² | 0.213 in² | 0.282 in² |
| 1" | 1.049 in | 0.864 in² | 0.259 in² | 0.268 in² | 0.346 in² | 0.458 in² |
| 1-1/4" | 1.380 in | 1.496 in² | 0.449 in² | 0.464 in² | 0.598 in² | 0.793 in² |
| 1-1/2" | 1.610 in | 2.036 in² | 0.611 in² | 0.631 in² | 0.814 in² | 1.079 in² |
| 2" | 2.067 in | 3.356 in² | 1.007 in² | 1.040 in² | 1.342 in² | 1.779 in² |
| 2-1/2" | 2.731 in | 5.858 in² | 1.757 in² | 1.816 in² | 2.343 in² | 3.105 in² |
| 3" | 3.356 in | 8.846 in² | 2.654 in² | 2.742 in² | 3.538 in² | 4.688 in² |
| 3-1/2" | 3.834 in | 11.545 in² | 3.463 in² | 3.579 in² | 4.618 in² | 6.119 in² |
| 4" | 4.334 in | 14.753 in² | 4.426 in² | 4.573 in² | 5.901 in² | 7.819 in² |
IMC conduit fill areas
Dimensional source: Wheatland Tube, Steel Intermediate Metal Conduit brochure. Verify the exact manufacturer product and project requirements before use.
| Trade size | Inside diameter | Internal area | 30% area | 31% area | 40% area | 53% area |
|---|---|---|---|---|---|---|
| 1/2" | 0.660 in | 0.342 in² | 0.103 in² | 0.106 in² | 0.137 in² | 0.181 in² |
| 3/4" | 0.869 in | 0.593 in² | 0.178 in² | 0.184 in² | 0.237 in² | 0.314 in² |
| 1" | 1.105 in | 0.959 in² | 0.288 in² | 0.297 in² | 0.384 in² | 0.508 in² |
| 1-1/4" | 1.448 in | 1.647 in² | 0.494 in² | 0.511 in² | 0.659 in² | 0.873 in² |
| 1-1/2" | 1.683 in | 2.225 in² | 0.667 in² | 0.690 in² | 0.890 in² | 1.179 in² |
| 2" | 2.150 in | 3.631 in² | 1.089 in² | 1.126 in² | 1.452 in² | 1.924 in² |
| 2-1/2" | 2.557 in | 5.135 in² | 1.540 in² | 1.592 in² | 2.054 in² | 2.722 in² |
| 3" | 3.176 in | 7.922 in² | 2.377 in² | 2.456 in² | 3.169 in² | 4.199 in² |
| 3-1/2" | 3.671 in | 10.584 in² | 3.175 in² | 3.281 in² | 4.234 in² | 5.610 in² |
| 4" | 4.166 in | 13.631 in² | 4.089 in² | 4.226 in² | 5.452 in² | 7.224 in² |
RMC conduit fill areas
Dimensional source: Wheatland Tube, DuraGuard Rigid Metal Conduit brochure. Verify the exact manufacturer product and project requirements before use.
| Trade size | Inside diameter | Internal area | 30% area | 31% area | 40% area | 53% area |
|---|---|---|---|---|---|---|
| 1/2" | 0.632 in | 0.314 in² | 0.094 in² | 0.097 in² | 0.126 in² | 0.166 in² |
| 3/4" | 0.836 in | 0.549 in² | 0.165 in² | 0.170 in² | 0.220 in² | 0.291 in² |
| 1" | 1.063 in | 0.887 in² | 0.266 in² | 0.275 in² | 0.355 in² | 0.470 in² |
| 1-1/4" | 1.394 in | 1.526 in² | 0.458 in² | 0.473 in² | 0.610 in² | 0.809 in² |
| 1-1/2" | 1.624 in | 2.071 in² | 0.621 in² | 0.642 in² | 0.828 in² | 1.098 in² |
| 2" | 2.083 in | 3.408 in² | 1.022 in² | 1.056 in² | 1.363 in² | 1.806 in² |
| 2-1/2" | 2.489 in | 4.866 in² | 1.460 in² | 1.508 in² | 1.946 in² | 2.579 in² |
| 3" | 3.090 in | 7.499 in² | 2.250 in² | 2.325 in² | 3.000 in² | 3.974 in² |
| 3-1/2" | 3.570 in | 10.010 in² | 3.003 in² | 3.103 in² | 4.004 in² | 5.305 in² |
| 4" | 4.050 in | 12.882 in² | 3.865 in² | 3.993 in² | 5.153 in² | 6.827 in² |
| 5" | 5.073 in | 20.212 in² | 6.064 in² | 6.266 in² | 8.085 in² | 10.712 in² |
| 6" | 6.093 in | 29.158 in² | 8.747 in² | 9.039 in² | 11.663 in² | 15.454 in² |
PVC Schedule 40 conduit fill areas
Dimensional source: JM Eagle, Solvent Weld PVC Electrical Conduit Schedule Series data sheet. Verify the exact manufacturer product and project requirements before use.
| Trade size | Inside diameter | Internal area | 30% area | 31% area | 40% area | 53% area |
|---|---|---|---|---|---|---|
| 1/2" | 0.622 in | 0.304 in² | 0.091 in² | 0.094 in² | 0.122 in² | 0.161 in² |
| 3/4" | 0.824 in | 0.533 in² | 0.160 in² | 0.165 in² | 0.213 in² | 0.282 in² |
| 1" | 1.049 in | 0.864 in² | 0.259 in² | 0.268 in² | 0.346 in² | 0.458 in² |
| 1-1/4" | 1.380 in | 1.496 in² | 0.449 in² | 0.464 in² | 0.598 in² | 0.793 in² |
| 1-1/2" | 1.610 in | 2.036 in² | 0.611 in² | 0.631 in² | 0.814 in² | 1.079 in² |
| 2" | 2.067 in | 3.356 in² | 1.007 in² | 1.040 in² | 1.342 in² | 1.779 in² |
| 2-1/2" | 2.469 in | 4.788 in² | 1.436 in² | 1.484 in² | 1.915 in² | 2.538 in² |
| 3" | 3.068 in | 7.393 in² | 2.218 in² | 2.292 in² | 2.957 in² | 3.918 in² |
| 3-1/2" | 3.548 in | 9.887 in² | 2.966 in² | 3.065 in² | 3.955 in² | 5.240 in² |
| 4" | 4.026 in | 12.730 in² | 3.819 in² | 3.946 in² | 5.092 in² | 6.747 in² |
| 5" | 5.047 in | 20.006 in² | 6.002 in² | 6.202 in² | 8.002 in² | 10.603 in² |
| 6" | 6.065 in | 28.890 in² | 8.667 in² | 8.956 in² | 11.556 in² | 15.312 in² |
PVC Schedule 80 conduit fill areas
Dimensional source: JM Eagle, Solvent Weld PVC Electrical Conduit Schedule Series data sheet. Verify the exact manufacturer product and project requirements before use.
| Trade size | Inside diameter | Internal area | 30% area | 31% area | 40% area | 53% area |
|---|---|---|---|---|---|---|
| 1/2" | 0.546 in | 0.234 in² | 0.070 in² | 0.073 in² | 0.094 in² | 0.124 in² |
| 3/4" | 0.742 in | 0.432 in² | 0.130 in² | 0.134 in² | 0.173 in² | 0.229 in² |
| 1" | 0.957 in | 0.719 in² | 0.216 in² | 0.223 in² | 0.288 in² | 0.381 in² |
| 1-1/4" | 1.278 in | 1.283 in² | 0.385 in² | 0.398 in² | 0.513 in² | 0.680 in² |
| 1-1/2" | 1.500 in | 1.767 in² | 0.530 in² | 0.548 in² | 0.707 in² | 0.937 in² |
| 2" | 1.939 in | 2.953 in² | 0.886 in² | 0.915 in² | 1.181 in² | 1.565 in² |
| 2-1/2" | 2.323 in | 4.238 in² | 1.271 in² | 1.314 in² | 1.695 in² | 2.246 in² |
| 3" | 2.900 in | 6.605 in² | 1.982 in² | 2.048 in² | 2.642 in² | 3.501 in² |
| 3-1/2" | 3.364 in | 8.888 in² | 2.666 in² | 2.755 in² | 3.555 in² | 4.711 in² |
| 4" | 3.826 in | 11.497 in² | 3.449 in² | 3.564 in² | 4.599 in² | 6.093 in² |
| 5" | 4.813 in | 18.194 in² | 5.458 in² | 5.640 in² | 7.278 in² | 9.643 in² |
| 6" | 5.761 in | 26.067 in² | 7.820 in² | 8.081 in² | 10.427 in² | 13.816 in² |
Important limitations
These are area comparisons, not complete cable-pull evaluations. Bend radius, pulling tension, sidewall pressure, jamming risk, pathway length, environmental conditions, and project specifications may justify a larger conduit or lower fill.
Why trade sizes cannot simply be added
Conduit capacity is based on circular area, not the sum of the trade-size labels. See the dimensional proof comparing one 4-inch EMT with four 2-inch EMT conduits.