Conduit Wire Fill Charts - Common Conversions - and Per National Electrical Code Chapter 9 Table 4

Oct 12, 2026

Conduit wire fill charts providing practical conversion factors and conduit capacity tables for different conduit types. The document includes common unit conversions for length, weight, and temperature between metric and imperial systems. It also presents National Electrical Code chapter-based fill information for flexible metal and flexible nonmetallic conduit options, listing trade size, internal diameter, and total cross-sectional area for 100% fill, as well as allowable fill areas for 2 wires, over 2 wires, and 1 wire.

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CategoryPresentations

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Pages2

Reading Time1 min

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Common Conversions

Length

Weight

Temperature

Conduit Wire Fill Charts

Flexible Metal Conduit (BR, ABR)

Liquidtight Flexible Metal Conduit (LA, LT, EF, ATLA, etc.)

Flexible Nonmetallic Conduit Type A-LNMP

Liquidtight Nonmetallic Conduit Type B (NM, NMHT, NMFG, NM2)

NPT Threaded Fittings

Conduit Wire Fill Charts Common Conversions | LENGTH
1 Foot = 0.305 Meters | WEIGHT
1 Pound = 454 Grams | TEMPERATURE
°C = Degrees Centigrade | | --- | --- | --- | | 1 Meter = 3.281 Feet | 1 Pound = 0 .454 Kilograms | °F = Degrees Fahrenheit | | 1 Inch = 25.4 Millimeters | 1 Kilogram = 2.205 Pounds | °C = (°F-32) ÷ 1.8 | | 1 Millimeter = 0.039 Inches | 1 Gram = 0.035 Ounces | °F = (°C x 1 .8) + 32 | | 1 Inch = 2.54 Centimeters | 1 Ounce = 28.349 Grams | | | 1 Centimeter = 0.394 Inches | | | | CONDUIT WIRE FILL CHARTS
Per National Electrical Code-Chapter 9, Table 4 | | | | | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Flexible Metal Conduit-BR, ABR | | | | | | Liquidtight Flexible Metal Conduit-LA, LT, EF, ATLA, AT, ATX, ALT, ZHLA,
CEA, CSA, VJC, LAFG, LSSFG, LTSS, ZHSS, ATXSS, ATSS, CBLA | | | | | | Trade
Size (in.) | Internal
Diameter (in.) | Total
Area
100%
([sq. in](sq. in).) | 2
Wires
31%
(sq.
in.) | Over 2
Wires
40%
([sq. in](sq. in).) | 1 wire
53%
(sq.
in.) | Internal Diameter
(in.) | TotalArea
100%
([sq. in](sq. in).) | 2 Wires
31%
([sq. in](sq. in).) | Over 2 Wires
40%
([sq. in](sq. in).) | 1 wire
53%
([sq. in](sq. in).) | | 3/8 | 0.384 | 0.116 | 0.036 | 0.046 | 0.061 | 0.494 | 0.192 | 0.060 | 0.077 | 0.102 | | 1/2 | 0.635 | 0.317 | 0.098 | 0.127 | 0.168 | 0.632 | 0.314 | 0.097 | 0.126 | 0.166 | | 3/4 | 0.824 | 0.533 | 0.165 | 0.213 | 0.282 | 0.83 | 0.541 | 0.168 | 0.216 | 0.287 | | 1 | 1.02 | 0.817 | 0.253 | 0.327 | 0.433 | 1.054 | 0.872 | 0.27 | 0.349 | 0.462 | | 1-1/4 | 1.275 | 1.277 | 0.396 | 0.511 | 0.677 | 1.395 | 1.528 | 0.474 | 0.611 | 0.81 | | 1-1/2 | 1.538 | 1.857 | 0.576 | 0.743 | 0.984 | 1.588 | 1.979 | 0.613 | 0.792 | 1.049 | | 2 | 2.04 | 3.269 | 1.013 | 1.308 | 1.733 | 2.033 | 3.245 | 1.006 | 1.298 | 1.72 | | 2-1/2 | 2.5 | 4.909 | 1.522 | 1.964 | 2.602 | 2.493 | 4.879 | 1.512 | 1.952 | 2.586 | | 3 | 3 | 7.069 | 2.191 | 2.828 | 3.747 | 3.085 | 7.475 | 2.317 | 2.99 | 3.962 | | CONDUIT WIRE FILL CHARTS | | | | | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 3-1/2 | 3.5 | 9.621 | 2.983 | 3.848 | 5.099 | 3.52 | 9.731 | 3.017 | 3.892 | 5.157 | | 4 | 4 | 12.566 | 3.895 | 5.026 | 6.66 | 4.02 | 12.692 | 3.935 | 5.077 | 6.727 | | Flexible Nonmetallic Conduit Type A-LNMP | | | | | | Liquidtight Nonmetallic Conduit Type B-NM, NMHT, NMFG, NM2 | | | | | | Trade
Size (in.) | Internal
Diameter (in.) | Total
Area
100%
([sq. in](sq. in).) | 2
Wires
31%
(sq.
in.) | Over 2
Wires
40%
([sq. in](sq. in).) | 1 wire
53%
(sq.
in.) | Internal Diameter
(in.) | TotalArea
100%
([sq. in](sq. in).) | 2 Wires
31%
([sq. in](sq. in).) | Over 2 Wires
40%
([sq. in](sq. in).) | 1 wire
53%
([sq. in](sq. in).) | | 3/8 | 0.495 | 0.192 | 0.06 | 0.077 | 0.102 | 0.494 | 0.192 | 0.06 | 0.077 | 0.102 | | 1/2 | 0.63 | 0.312 | 0.097 | 0.125 | 0.165 | 0.632 | 0.314 | 0.097 | 0.126 | 0.166 | | 3/4 | 0.825 | 0.535 | 0.166 | 0.214 | 0.284 | 0.83 | 0.541 | 0.168 | 0.216 | 0.287 | | 1 | 1.043 | 0.854 | 0.265 | 0.342 | 0.453 | 1.054 | 0.872 | 0.27 | 0.349 | 0.462 | | 1-1/4 | 1.383 | 1.501 | 0.465 | 0.6 | 0.796 | 1.395 | 1.528 | 0.474 | 0.611 | 0.81 | | 1-1/2 | 1.603 | 2.017 | 0.625 | 0.807 | 1.069 | 1.588 | 1.979 | 0.613 | 0.792 | 1.049 | | 2 | 2.063 | 3.341 | 1.036 | 1.336 | 1.771 | 2.033 | 3.245 | 1.006 | 1.298 | 1.72 | | NPT Threaded Fittings | | | | | | NPT Threaded Fittings-Knock Out Diameter | | | | | | 3/8 | 1/2 | | | | | 7/8 | | | | | | 1/2 | 1/2 | | | | | 7/8 | | | | | | 3/4 | 3/4 | | | | | 1-3/32 | | | | | | 1 | 1 | | | | | 1-23/64 | | | | | | 1-1/4 | 1-1/4 | | | | | 1-23/32 | | | | | | 1-1/2 | 1-1/2 | | | | | 2 | | | | | | 2 | 2 | | | | | 2-1/2 | | | | |

FAQs

What unit conversion factors are included for quick estimating?

The charts provide conversions for length (feet/meters, inches/millimeters, inches/centimeters), weight (pounds/grams and kilograms/pounds/ounces), and temperature (°C to °F and °F to °C).

How are conduit wire fill capacities organized in the tables?

Each conduit type section lists trade size, internal diameter, total area at 100% fill, and allowable areas for 2 wires, over 2 wires, and 1 wire.

Where does the wire fill chart data reference come from?

The conduit wire fill tables are stated as per the National Electrical Code, Chapter 9, Table 4.

Oct 12, 2026

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