VoltDrop

The voltage drop calculator that explains itself. No signup, no guessing.

🚇 Conduit Fill

How big a conduit do you need for your wires? Enter what you're pulling, get the smallest legal size.

EMT is the common thin-wall metal tubing. PVC Sch 40 is the gray plastic conduit.

Sizes are for standard THHN/THWN insulated building wire — the most common single-conductor wire pulled in conduit.

wires

Count every insulated wire in the pipe, including the neutral and an insulated ground. All one size for now — mixed sizes coming.

The fill rules, in plain English

Wires need free space in a conduit — jam it full and you can't pull them through, and they can overheat. The standard U.S. limits (NEC Chapter 9): one wire may fill 53% of the pipe's inside area, two wires 31%, and three or more 40%. We do that area math for you using the official wire and conduit dimensions.

Good to know: long runs with lots of bends are easier with a size bigger than the legal minimum — many electricians upsize on purpose. This tool covers one wire size at a time; mixed-size pulls are coming.