NEC 2023 Electrical Calculators

Interactive study tools for the National Electrical Code

⚡

Conductor Ampacity Sizing

Cable sizing with temperature correction and conduit-fill derating. Full NEC Table 310.16 with adjustment factors.

NEC 310.16 · 310.15(B) · 310.15(C)
📉

Voltage Drop

Single-phase and three-phase voltage drop calculation with percent check. Includes reverse calculator for minimum conductor size.

NEC 210.19(A) · 215.2(A)(1)
🏠

Dwelling Unit Load Calculation

Article 220 step-by-step residential load calculation — general lighting, appliances, range, dryer, HVAC, and service sizing.

NEC Art. 220 · Table 220.42 · 220.55
📦

Box & Conduit Fill

Box fill per 314.16 with itemized conductor allowances, plus raceway fill per Chapter 9 Tables 1, 4, and 5.

NEC 314.16 · Ch. 9 Table 1 · Annex C
🔌

OCPD / Breaker Sizing

Overcurrent protection device sizing for continuous and non-continuous loads with 240.4(B) next-size-up rule and conductor check.

NEC 240.6(A) · 210.20(A) · 240.4(B)
⚙️

Motor Calculations

Full-load current lookup, conductor sizing at 125%, branch-circuit OCPD by protection type, and overload protection settings.

NEC Art. 430 · Tables 430.248/250
🔗

Grounding & Bonding Conductors

GEC sizing (Table 250.66), EGC sizing (Table 250.122), and main/supply-side bonding jumper sizing for Cu and Al.

NEC 250.66 · 250.122 · 250.28/102
⚠ Study Aid Only — These calculators are for educational purposes. Verify against the adopted code edition and consult a licensed professional before use in real project or estimate documentation.