Electrical & HVAC Job-Site Calculator Hub (5-in-1)

Fast, code-referenced calculators for electricians, HVAC techs, and engineers—all on one page or via dedicated tools above.

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1. NEC Conduit Fill Calculator (Chapter 9, Tables 1, 4 & 5)

Conduit Material

Conduit Trade Size

Conduit Nipple ≤ 24" (60% Fill)

Primary Wire Insulation

Primary Wire Gauge

Primary Wire Count

Secondary / Ground Insulation

Secondary / Ground Gauge

Secondary Wire Count

Trade Size	Internal Dia.	Total Area	Bundle Fill %	Max Primary Wires	NEC Status

Load Current (Amps)

Conductor Metal

Terminal Temp Rating

Conductors in Raceway

Continuous Load (runs 3+ hours continuously — apply NEC 125% rule)

System Phase

Conductor Metal

System Voltage (V)

Wire Gauge

One-Way Run Length (Feet)

Load Current (Amps)

Transformer Phase

Primary Voltage (V)

Secondary Voltage (V)

Secondary Load (Amps)

Include 25% Future Expansion & Continuous Margin (1.25x)

Room Length (ft)

Room Width (ft)

Ceiling Height (ft)

Target Air Changes / Hr (ACH)

Direct job-site answers for the most common wire and conduit combinations: