1-1/2" Conduit Wire Fill Calculator

Free online tool • 2026 NEC Compliant

1.5-inch conduit (trade size 1-1/2") is one of the most common sizes used in residential and commercial branch circuit and feeder runs. Select your conduit type and wire gauges below to calculate NEC-compliant fill. Per NEC Chapter 9, Table 1, the maximum fill for three or more conductors is 40% of the conduit's internal cross-sectional area.

Internal Area: 0.533 in²Fill Limit: 40%(3 conductors)

Conductors

THHN / THWN-2

Results

PASS
7.5%Limit: 40%

Total Conductors

3

Wire Area Used

0.0399 in²

Remaining Space

0.1733 in²

How to Use This Calculator

1

Select conduit type

Choose EMT, PVC Schedule 40/80, RMC, or FMC.

2

Set trade size to 1-1/2"

The calculator pre-selects 1-1/2" conduit for this page.

3

Add your wire rows

Enter each wire gauge and quantity.

4

Check fill result

Verify the calculated fill percentage is at or below the NEC limit.

Frequently Asked Questions

How many 12 AWG wires fit in 1-1/2" conduit?

In 1-1/2" EMT (internal area 2.036 in², 40% limit = 0.814 in²), each 12 AWG THHN wire occupies 0.0133 in². You can fit approximately 61 conductors. However, actual fills should always be checked against the NEC fill percentage for your specific number of conductors.

How many 10 AWG wires fit in 1-1/2" conduit?

In 1-1/2" EMT, at the 40% fill limit (0.814 in²), each 10 AWG THHN wire occupies 0.0211 in². You can fit approximately 38 conductors.

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