WireFillChart

WireFillChart is a free, browser-based NEC 2023 wire fill chart and conduit fill calculator for US electricians, inspectors, engineers and students. It covers EMT, IMC, RMC, PVC, flex and other raceways using NEC Chapter 9 Tables 1, 4 and 5, and shows a live fill percentage, the NEC status and a jamming-risk hint. Charts are printable.

The site also has nine more calculators, including box fill and voltage drop. There is no signup, and the site carries ads. The footer reads Reference Only, Verify with current code, so check results against the adopted code and your AHJ.