ConduitLab: NEC Calculator

ConduitLab is a professional NEC-based electrical calculator for ampacity, voltage drop, conduit fill, wire sizing, and clean PDF jobsite reports. Built for electricians, inspectors, contractors, foremen, and engineers, ConduitLab helps you run fast, repeatable electrical calculations without digging through scattered notes or generic calculator apps. CORE ELECTRICAL CALCULATIONS Ampacity — real-world derating applied Calculate wire sizing with ambient temperature correction, rooftop exposure adjustments, terminal temperature limits, conductor count effects, conductor bundling, and continuous-load factors applied together. Voltage Drop — catch issues before inspection Run voltage drop calculations for branch circuits and feeders, including single-phase and 3-phase work, long runs, and advanced exact AC options. Conduit Fill — see it before you pull Apply NEC Chapter 9 conduit fill limits and use visual feedback to help prevent jams, rework, and failed installs. Nipple Exception Supports the 24-inch nipple exception with 60% fill where applicable. INSPECTOR-READY PDF REPORTS Generate clean, professional PDF reports for inspections, submittals, field documentation, and permanent records. Reports can include: • Project inputs and calculated results • Ampacity, voltage drop, and conduit fill summaries • NEC-based citations by edition • Clear documentation for field review LITE AND PRO OPTIONS ConduitLab Lite supports common residential and light commercial calculations with practical limits. ConduitLab Pro unlocks: • Full wire size range up to 2000 kcmil • 3-phase and exact voltage drop tools • Interactive 2D conduit fill visualization • X-Ray conduit visualizer mode • Unlimited PDF exports • Expanded professional features BUILT FOR JOBSITE USE • Offline-first calculations • Fast, deterministic results • No account required • Multi-edition NEC support • Designed for real field workflows IMPORTANT DISCLAIMER ConduitLab is a reference and documentation tool only. It does not provide engineering services or code-compliance certification. Users are responsible for verifying all results and complying with applicable electrical codes, local amendments, and Authority Having Jurisdiction requirements. Subscriptions unlock advanced features and unlimited PDF exports.