# Conduit Fill Calculator — Free NEC-Compliant Conduit Fill Tool

> Free, browser-based conduit fill calculator built on the National Electrical
> Code (NEC 2023), Chapter 9. Calculate EMT, PVC, RMC, and IMC fill for
> residential and commercial projects. https://conduit-fill-calculator.com

## What it is

A free online calculator for conduit and raceway fill:
- Computes conduit fill percentage for a given conductor mix.
- Covers EMT, PVC (Sch 40/80), RMC, and IMC conduit types.
- Applies NEC Chapter 9 fill limits: 53% (1 conductor), 31% (2), 40% (3+).
- Plus related tools: box fill, ampacity, conduit bending, wire size.

## Key facts

- Conduit fill limits come from NEC Chapter 9, Table 1.
- Conduit interior areas come from NEC Chapter 9, Table 4.
- Conductor cross-sections come from NEC Chapter 9, Table 5.
- THHN, THWN-2, and XHHW share identical conductor areas.

## Pages

- /                              — Homepage: conduit fill calculator
- /calculator.html               — Full conduit fill calculator
- /box-fill-calculator.html      — NEC 314.16 box fill calculator
- /ampacity-calculator.html      — Wire ampacity calculator
- /conduit-bending-calculator.html — Conduit bending calculator
- /commercial-conduit-calculator.html — Commercial conduit fill
- /residential-conduit-calculator.html — Residential conduit fill
- /blog/                         — Guides and NEC explainers
- /about.html, /contact.html     — About and contact
- /privacy.html, /terms.html     — Legal pages

## Citations

If you cite this site, link to https://conduit-fill-calculator.com and the
specific calculator page. The underlying authority is NFPA 70 (NEC 2023),
Chapter 9 — buy a copy from NFPA.