Wire Gauge Calculator

Instantly convert AWG to diameter in millimeters and inches, cross-sectional area in mm², kcmil, and circular mils. Covers standard sizes from 18 AWG through 4/0 AWG, following ASTM B258 geometry. Smaller AWG numbers mean thicker wire — the app makes the relationship clear at a glance.

Look up conductor ampacity directly from NEC Table 310.16 for copper and aluminum. Values are shown for 60°C, 75°C, and 90°C insulation ratings at standard ambient conditions, so you can size conductors against the correct temperature column for the installation.

Enter voltage, current, run length, and allowable drop percentage to get exact voltage drop in volts and percent. The app uses the standard resistance formula VD = 2 × L × I × (R ÷ 1000) and supports both feet and meters, with quick-fill buttons for 12V, 24V, 120V, and 240V systems.

The app automatically compares calculated voltage drop against the NEC-recommended 3% branch-circuit limit. A green/red pass-fail indicator makes compliance obvious, and the result notes whether the conductor size is limited by voltage drop or by ampacity — a distinction that prevents oversizing or undersizing.

Switch between copper and aluminum conductors, with material-specific resistance and ampacity values. The app also supports standard conductor insulation types and provides the data needed to compare material performance for cost and voltage-drop trade-offs.

Generate clear calculation summaries showing wire size, ampacity, voltage drop, and compliance status. Export results for project records, inspections, or client documentation. All calculations run offline on-device, with no account or internet required.