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Free Electrical Load Calculator

Electrical Load Calculator

Estimate a residential electrical service load using the NEC 220.82 optional method. Enter the living area, appliances, and HVAC loads to calculate the estimated service load in amps and see an estimated service size. Results update as you enter your information. No signup, no email.

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Calculate Your Electrical Service Load with Arrivy

Enter the dwelling's living area, appliance loads, and heating and cooling information. The calculator updates the estimated load and service-size estimate as you work.

Dwelling

NEC 220.82 optional method for a single-family dwelling.

Living area

ft²

Service voltage

Small-appliance circuits (min 2)

Laundry circuits

Appliances & equipment

Nameplate VA (watts). Leave 0 if not present.

Range / oven

Water heater

Dryer

Dishwasher

Other fixed appliances

EV charger

Heating & cooling

The larger of the two is counted (they don’t run together).

Heating

A/C / cooling

Recommended service size

0 A

Calculated load

0 A

Demand

Headroom

Demand load (VA)

Connected load

Demand load

Calculated amps

0 A

Service size

0 A

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How the NEC 220.82 Optional Method Works

The NEC 220.82 optional method provides a simplified approach for calculating the service load of a dwelling. The calculator follows this basic sequence:

1. Calculate the general loads. Apply 3 VA per square foot for general lighting and general-use receptacles, add the required small-appliance and laundry loads, and include applicable appliances and motors at their required ratings
2. Apply the demand factor. The first 10,000 VA of the applicable general load is calculated at 100%, with the portion above 10,000 VA calculated at 40%.
3. Add the larger heating or cooling load Heating and air-conditioning loads are not added together. The larger applicable load is used.
4. Convert the calculated VA to amps. The calculated volt-amp load is converted to amperes using the applicable service voltage.
5. Compare with a service size. The calculated load is compared with available standard service sizes to identify a service size that can accommodate the estimated demand.

How to Count as the Load

This section lists the key electrical loads—including lighting, circuits, appliances, HVAC, and future expansions—used to size a residential service. It breaks down how each component factors into determining overall power capacity.

General lighting and general-use receptacles

3 VA per square foot of applicable dwelling area.

Small-appliance & laundry circuits

1,500 VA each, with a minimum of two small-appliance circuits plus one laundry circuit.

Fixed appliances

Range, water heater, dryer, dishwasher, disposal, and similar loads at their applicable nameplate ratings.

Large added loads

EV chargers especially; they can push an existing service over its available capacity.

Heating or cooling

The larger of the two, rather than both, is included in the calculation.

Future loads

Consider known or planned future loads when evaluating service capacity. The appropriate service size depends on the calculated demand, available service sizes, and applicable requirements.

Frequently Asked Questions

The calculator is based on the NEC 220.82 optional method, which provides an optional approach for calculating the service load of qualifying dwelling units. However, the calculator output is an estimate, not a permit-ready load calculation. A qualified electrician should verify the calculation, account for local code requirements and amendments, and complete any documentation required for permitted work.

This calculator uses the NEC 220.82 optional method. It applies the specified demand factors to the applicable dwelling loads rather than using the separate demand calculations of the standard method. The method that applies depends on the dwelling and the requirements of the applicable code.

Under the optional-method approach, the calculation uses the larger applicable heating or cooling load rather than adding both together. Heating and cooling loads are treated as noncoincident loads for this calculation. The actual requirements depend on the equipment and circumstances of the installation.

An EV charger can add a significant continuous load to a home's electrical demand. Depending on the charger and its rating, that additional load can materially change the calculated service requirement. If an EV charger is planned, include its applicable load when evaluating the service capacity rather than checking the existing service without it.

Don't treat a fixed percentage as a substitute for the actual load calculation. The service should be sized based on the calculated demand and applicable requirements, while expected future loads can also be considered when choosing between available service sizes. A qualified electrician can determine whether additional capacity makes sense for the property.

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