What is the NEC 220.82 optional method?

It is a simplified way to calculate the service load for a single dwelling. You total the general loads (lighting at 3 VA per square foot, small-appliance and laundry circuits, and fixed appliances), take the first 10,000 VA at 100 percent and the remainder at 40 percent, then add the larger of the heating or cooling load. Dividing by 240 V gives the amps.

What size electrical service does a house need?

It depends on the calculated load. Many homes land under 100 A, while all-electric homes with a range, dryer, water heater, and EV charger often need 200 A. This calculator recommends the next standard size up from 100, 125, 150, 200, 225, or 400 A based on your inputs.

Does an EV charger require a service upgrade?

Often, but not always. A typical Level 2 charger adds around 7,200 VA of continuous load, and because it lands in the portion of the general load taken at 40 percent under 220.82, the impact on the calculated amps can be smaller than expected. Run the numbers before assuming a panel upgrade is needed.

Can I use this calculation to pull a permit?

No. This is an estimate for sanity-checking, built on a simplified version of the NEC 220.82 optional method. The Canadian CEC Section 8 calculation differs, and local amendments apply everywhere. Final service and conductor sizing must be done by a licensed electrician and approved by your local AHJ.

Residential Electrical Load Calculator

Estimate a home's electrical service load with the NEC 220.82 optional method. Get total VA, amps, and a recommended panel size with a full breakdown.

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Estimate the service load

Enter the dwelling details below. The calculation follows the NEC 220.82 optional method and updates as you type.

The Home

General lighting is figured at 3 VA per square foot; each small-appliance and laundry circuit adds 1,500 VA.

Floor Area (sq ft)

Livable area, per the outside dimensions

Small-Appliance Circuits

Kitchen/dining receptacle circuits

Laundry Circuits

Fixed Appliances

Nameplate ratings in VA. Edit to match the actual equipment, or zero out anything the home does not have.

Electric Range

Typical: 12,000 VA

Water Heater

Typical: 4,500 VA

Clothes Dryer

Typical: 5,000 VA

Dishwasher

Typical: 1,200 VA

Microwave

Typical: 1,500 VA

Garbage Disposal

Typical: 900 VA

EV Charger

Typical Level 2: 7,200 VA

Other Fixed Appliances

Pool pump, hot tub, etc.

Heating & Cooling

Enter both loads; the larger of the two is applied at 100%. (This simplifies NEC 220.82(C), which has separate factors for heat pumps and staged electric heat.)

Electric Heating Load (VA)

Furnace, baseboards, or heat pump + supplemental heat

Cooling Load (VA)

Air conditioner or heat pump in cooling

Enter the floor area to calculate the service load

You'll get total VA, amps, a recommended service size, and a full breakdown.

This is an estimate, not a permit document

Figures follow the NEC 220.82 optional method for a single dwelling, with the heating/cooling comparison simplified. The Canadian CEC Section 8 calculation differs. Final service and conductor sizing must be done by a licensed electrician and approved by your local AHJ.

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