About ConduitCount

ConduitCount is for electricians who count material before the supply-house run and check fill before the pull. It is free, works on a phone with gloves on, and keeps nothing about you.

Where the numbers come from

• Conduit inside areas: NEC Chapter 9, Table 4.
• Wire areas with insulation: Chapter 9, Table 5.
• Fill percentages and notes: Chapter 9, Table 1 and its notes.
• Resistance for voltage drop: Chapter 9, Table 8.
• Box volumes and allowances: 314.16(A) and (B).
• Support spacing: 342.30, 344.30, 348.30, 350.30, 352.30, 358.30, 362.30.
• Ampacity and adjustment: Table 310.16 and Table 310.15(C)(1).

Values are from the 2023 NEC. Each table was checked against at least two published copies (manufacturer data, training references) and the fill charts are tested against Annex C. The sources we checked are listed on the sources page.

Check your code

Your jurisdiction may be on an older edition or have local amendments, and the inspector has the last word. ConduitCount shows the math so you can check it.

Spotted a wrong number?

Write to [email protected] with the page and what you expected. We fix errors the same week.

Who makes it

ConduitCount is made by Moltke Benjaminsen, a small studio that builds focused tools.