Conduit Fill Chart — NEC Chapter 9
Free download · 85 × 54mm (credit card size)
Conduit fill calculations are one of the most common tasks for US electricians. This pocket card gives you the NEC Chapter 9 fill percentages (40% for 3+ conductors, 31% for 2, 53% for 1) and a quick-lookup table showing the maximum number of THHN/THWN conductors per EMT conduit size for 6 trade sizes (1/2" to 2") and 7 AWG sizes. No more flipping through Chapter 9 tables on the job site. The back covers conduit type comparisons (EMT, RMC, PVC, FMC, LFMC), the nipple fill exception (60% for conduits ≤24"), and trade size to metric equivalents. Scan the QR code for our online conduit fill calculator that handles mixed conductor sizes and all raceway types.
What's Included
How to Print
- ●Recommended paper: 250–300gsm cardstock
- ●Print double-sided, flip on short edge
- ●Cut along crop marks with a paper trimmer
- ●Laminate with 80–125 micron pouches for durability
- ●Fits in wallet, toolbox, or pocket
Try the Interactive Calculator
Need precise calculations beyond quick reference? Try our free online calculator with full clause references and professional report output.
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Frequently Asked Questions
What paper should I print this on?
Print on 250–300gsm cardstock. Laminate for toolbox use. This card gets heavy daily use on residential and commercial job sites.
Can I distribute this to my team?
Yes. Free to print and distribute. Hand one to every journeyman and apprentice on the crew.
What standard does this reference?
This card references NEC/NFPA 70:2023, Chapter 9 Table 1 (conduit fill percentages), Table 4 (conduit dimensions), and Table 5 (conductor dimensions).
How often is this updated?
Updated with each NEC code cycle (every 3 years). Current card reflects NEC 2023.