Conduit Fill Calculator (EMT, THHN)
Pick a wire size and how many, and see the fill in each EMT size. Same size wires only.
Estimate only. Areas are based on NEC Chapter 9. Always check against the current code book and your AHJ. Derating for more than 3 current-carrying wires is a separate step.
Result
Fill in your numbers and hit Calculate.
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How the math works
Total wire area = area of one wire x number of wires
Percent fill = total wire area / conduit inside area x 100
Max fill: 1 wire 53%, 2 wires 31%, 3 or more 40%Wire and conduit areas used here are the published NEC Chapter 9 values for THHN/THWN-2 and EMT, trimmed to common sizes. Mixed sizes, other wire types, and other raceways need their own areas.
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