Conduit Fill Calculator - NEC

NEC conduit fill calculator. EMT, PVC, IMC sizes. THHN wire 14 AWG-1000 MCM.

NEC conduit fill calculator for electricians, apprentices, and electrical engineers. Calculate conduit fill percentages instantly using official NEC Chapter 9 data - Tables 1, 4, and 5. Works 100% offline on the job site.

Whether you're pulling THHN through EMT or sizing PVC for a big commercial run, this conduit fill calculator gives you accurate NEC-compliant results in seconds. Use it as your portable conduit fill chart and raceway fill reference - faster than looking up wire count tables manually.

CONDUIT FILL CALCULATOR FEATURES:
• 5 conduit types: EMT, IMC, RMC, PVC Schedule 40, PVC Schedule 80
• All standard trade sizes: 1/2" through 4"
• THHN/THWN-2 wire sizes: 14 AWG to 1000 MCM
• NEC Table 1 fill rules: 53% (1 wire), 31% (2 wires), 40% (3+ wires)
• Visual PASS/FAIL indicator with fill percentage
• Shows how many more wires you can add
• Suggests the next conduit size when you exceed fill capacity
• Mix different wire sizes in the same conduit fill calculation

PRO FEATURES (one-time purchase):
• No ads - clean interface for professionals
• Save conduit fill calculation history
• Export calculations as PDF reports for permits and records
• Dark theme support

BUILT FOR ELECTRICIANS ON THE JOB SITE:
This conduit fill calculator is designed by electricians, for electricians. The interface is clean, fast, and works with one hand. Add wires, see your fill percentage, and move on - no complicated menus or unnecessary features.

ACCURATE NEC CONDUIT FILL DATA:
All conduit and wire areas are sourced from the NEC Chapter 9. Conduit fill percentages follow NEC Table 1 rules exactly:
• 1 wire: 53% maximum fill
• 2 wires: 31% maximum fill
• 3 or more wires: 40% maximum fill

NEC TABLES INCLUDED:
• NEC Chapter 9, Table 1 - Percent fill for conduit and tubing
• NEC Chapter 9, Table 4 - Conduit dimensions and areas (EMT, IMC, RMC, PVC)
• NEC Chapter 9, Table 5 - Wire dimensions and areas (THHN, THWN-2)

PERFECT FOR:
• Licensed electricians doing conduit fill calculations daily
• Electrical apprentices studying for journeyman exams
• Electrical engineers and designers
• Electrical contractors bidding commercial and residential jobs
• NEC code exam preparation
• Anyone who needs a fast, accurate conduit fill calculator
• Conduit sizing and wire count on the job site

OFFLINE & PRIVACY:
• Works 100% offline - no internet needed on the job site
• No account required
• No data collection - your calculations stay on your device

Simplify your conduit fill calculations on the job site.