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Conduit Fill Calculator

NEC 2026 — Chapter 9, Table 1 / Table 4 / Table 5 & 5A

1
Conductors in Raceway

NEC Ch. 9, Table 5 / 5A

Add each conductor's size, insulation type, and quantity in this raceway — including the equipment grounding conductor if one is required. It is never added automatically.

2
Installation Options

NEC Ch. 9, Table 1, Note 4

Nipple — Conduit/Tubing ≤24 in. Long?

NEC Chapter 9, Table 1, Note 4: nipples 24 in. or less may be filled to 60% regardless of conductor count, overriding the standard 53%/31%/40% rule.

Conduit Fill Results

Smallest Fitting Trade Size by Conduit Type

Add at least one conductor row to calculate fill.

Disclaimer

The calculators and tools provided on this website ("EEE Corp Calculators") are intended for informational and preliminary design assistance purposes only. Results are based on the National Electrical Code (NEC/NFPA 70) and general industry practices as interpreted at the time of development, and may not reflect the most current code edition, local amendments, or Authority Having Jurisdiction (AHJ) requirements applicable to your project.

These calculators do not account for every possible electrical scenario, edge case, or site condition. Factors such as unusual load profiles, non-standard installation methods, environmental conditions, existing infrastructure limitations, and project-specific constraints may affect the correct design and are not necessarily captured by these tools.

These tools do not constitute professional engineering advice, and their output should not be relied upon as a substitute for review, calculation, and sign-off by a licensed Professional Engineer (P.E.) or qualified electrical professional. Local codes, utility requirements, and site-specific conditions can materially affect the correct design and sizing of electrical systems.

EEE Corp makes no warranty, express or implied, as to the accuracy, completeness, or fitness of these calculations for any particular installation. Use of this tool and its results is at your own risk, and EEE Corp assumes no liability for damages, code violations, permit rejections, or safety issues arising from reliance on calculator output. Always verify results against the applicable code edition and consult a licensed engineer or electrician before construction, installation, or permitting.