PANEL LOAD
PANEL LOAD
demand = NEC 220 standard method
ft²
kW
kW
kW
kW
kW
RESULT
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FILL IN ABOVE
NEC 220 Part III standard method, single-phase 240/120 V. Estimate only — actual service sizing requires a full Part III/IV worksheet by a licensed electrician and AHJ approval. Not a substitute for engineered drawings.
About this calculator
This panel load calculator estimates the total demand on a residential electrical service using the NEC 220 Part III "Standard Method." It applies 3 VA/ft² for general lighting and receptacles, 1500 VA per small-appliance and laundry circuit, then NEC 220.42 demand factors (100% of the first 3000 VA + 35% of the next 117,000 VA). Major appliances — range, dryer, water heater, HVAC, EV charger — are added at their nameplate or NEC-prescribed demand. The result is a service-size recommendation: 100 A, 150 A, 200 A, or 400 A. ESTIMATE ONLY — final service sizing must be done by a licensed electrician using the actual NEC 220 Part III or IV worksheet and verified by the local AHJ.
Common questions
Is 200-amp service enough for a typical home?
200 A handles most homes up to about 3,500 ft² with electric range, dryer, central AC, and a single Level-2 EV charger. Add a second EV, a hot tub, or whole-home electrification (heat pump + induction + heat-pump water heater) and 200 A starts feeling tight — plan for 320 A / 400 A class meter sockets up front.
What is the difference between Standard and Optional method?
NEC 220 Part III "Standard" method (used here) calculates each load with its own demand factor — accurate but conservative. Part IV "Optional" method uses a flat 100% on the first 10 kVA + 40% on the remainder for dwellings; for most all-electric homes it gives a smaller number than the Standard method. Either is code-legal.
Do I need to count gas appliances?
No. Only electric loads count toward the panel calculation. A gas range, gas dryer, or gas water heater contributes zero to the demand. The calculator is built so entering 0 kW for gas appliances drops them out cleanly.