Check how full a conduit is for a given set of conductors — with the fill percentage, the allowed percentage, and the smallest compliant size shown, never just a pass/fail.
For nine #12 THHN conductors in 3/4″ EMT, the engine returns:
22.5% fill in 3/4" EMT — COMPLIANT (40% allowed)
This example is rendered from the same calculation library the form above uses — it is computed at startup, never typed by hand, and a test compares it against the engine on every run.
Fill limits exist for two physical reasons: conductors in a crowded raceway run hotter, and pulling conductors through an overfilled conduit damages insulation. The calculation compares the total cross-sectional area of your conductors against the usable area of the conduit at the allowed fill percentage — which depends on how many conductors are in the run. The calculator shows the intermediate areas so a reviewer (or your journeyman) can follow the arithmetic instead of trusting a verdict.
Method scope, stated honestly: EMT/IMC/RMC/PVC-40/PVC-80, ½″–4″, THHN & XHHW only. Anything else fails loud rather than guessing.