EleCalculator

Residential Electrical calculator

Electrical Service Size Calculator

A 2,000 sq ft dwelling with a 12 kW range, 5 kW dryer, 4.5 kW water heater, 5 kW fixed loads, 7.68 kW EV charger, and 8.5 kW cooling screens at about 128.2A on 120/240V, so 150A is the next common service review. This page is an honest dwelling-service screen for U.S.-market planning work. It starts general lighting at 3 VA per square foot, adds the entered small-appliance and laundry circuits, screens one household cooking load and one dryer, adds the other fixed electric loads you entered, and then applies a first-10-kVA plus 40%-remainder demand treatment before adding the selected heating or cooling load. It is intentionally narrower than a full commercial, multifamily, or permit-package load study.

Updated July 16, 2026

A 2,000 sq ft dwelling with a 12 kW range, 5 kW dryer, 4.5 kW water heater, 5 kW of other fixed loads, a 7.68 kW EV charger, and 8.5 kW of cooling screens at about 128.2A on 120/240V, which is above 125A so the next common service review is 150A.

Demanded general load = first 10 kVA at 100% + 40% of the remainder, then add the selected heating or cooling load

Enter dwelling area, branch circuits, major electric loads, and the selected climate load to screen the next common dwelling service size

Calculator Inputs

Field notes

Calculation Results

Enter values above to see calculation results

Field kit

Tools for service review notes

Use the service-size result as a planning checkpoint, then compare measurement and labeling tools for documentation.

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Calculation history

Example Calculations

2,000 sq ft all-electric dwelling with EV chargingDwelling-service screen with one range, one dryer, cooling, and a 7.68 kW EV charger on 120/240V service.InputsService Voltage: 240Dwelling Area: 2000Small Appliance Circuits: 2Laundry Circuits: 1Cooking Load: 12Dryer Load: 5Water-Heater Load: 4.5Fixed Appliances: 5EV Charger Load: 7.68Climate Load Type: Air conditioningClimate Load: 8.5
1,500 sq ft dwelling with heat pump and no EVSESmaller dwelling-service screen using a heat-pump load on 120/240V service.InputsService Voltage: 240Dwelling Area: 1500Small Appliance Circuits: 2Laundry Circuits: 1Cooking Load: 10Dryer Load: 5Water-Heater Load: 4.5Fixed Appliances: 2.5Climate Load Type: Heat PumpClimate Load: 5

How to Use

How to use the electrical service size calculator

  1. Select the actual dwelling service voltage for the unit: 120/240V or 120/208V.
  2. Enter the dwelling area, then the required small-appliance and laundry circuits.
  3. Add the major electric loads you want this page to screen: one household cooking load, one dryer, water heater, other fixed appliances, and optional EV charger.
  4. Select the climate load mode that actually matches the dwelling and enter the associated heating or cooling load.
  5. If you are checking an existing panel upgrade, enter the existing service rating to compare the screened load current against the installed service size.

What the page returns

Output Meaning How to use it
General connected load block Dwelling lighting plus the entered appliance and EV loads before demand treatment See whether the entered dwelling is lightly or heavily electrified before demand factors are applied
Demanded general load First 10 kVA at 100% plus 40% of the remainder Use it as the main dwelling-load block for this page
Selected climate load The cooling or electric-heating load selected by the mode you chose Confirm that you selected the correct heating or cooling basis for the dwelling
Required service current Total calculated VA divided by the service voltage Use it to screen the next common service size and to compare against an existing service rating

Important scope notes

  • This page is for dwelling-service screening only. It does not size commercial, mixed-use, or house services for multifamily buildings.
  • The cooking screen is intentionally limited to one household range or cooking appliance. Multiple cooking appliances still need a dedicated table-based review.
  • The page gives a practical planning answer, not a permit verdict. Always verify the adopted NEC edition, local amendments, and utility rules.
  • Many users search for this as an Article 220 calculator, but NEC numbering and details can vary by adopted edition. Treat this page as a dwelling-screening workflow, not a substitute for a stamped load study.

Example: a 2,000 sq ft dwelling with one 12 kW range, one 5 kW dryer, one 4.5 kW water heater, 5 kW of other fixed appliances, a 7.68 kW EV charger, and 8.5 kW of cooling screens at about 30.8 kVA. On a 120/240V service, that is about 128A, so the next common service review is usually 150A.

Use the Residential Load Calculator for a broader dwelling demand screen, the Electrical Panel Load Calculator when the panel rating is the real question, the Breaker Sizing Calculator for branch-circuit protection, and the Wire Size Calculator when you need conductor sizing after the service load is screened.

Common Applications

Screening whether a one-family dwelling is likely to land near 100A, 150A, 200A, or larger service sizes
Checking whether an existing service is likely to feel tight after adding an EV charger or other major electric load
Comparing 120/240V and 120/208V dwellings for the same connected load
More applications. Open to review 2 additional use cases.
Explaining how all-electric equipment pushes a dwelling service upward
Supporting early service-upgrade conversations before a full design review

Frequently Asked Questions

How does this page estimate dwelling service size?
It builds a dwelling load block from floor area, small-appliance circuits, laundry circuits, and the electric loads you enter. It then takes the first 10 kVA at 100%, screens the remainder at 40%, adds the selected heating or cooling load, and converts the total VA to service current at the selected dwelling voltage.
Why does the page focus on one household range and one dryer?
Because the page is intentionally a practical dwelling screen, not a full schedule engine for multiple cooking appliances or multiple dryers. One range and one dryer cover a large share of one-family service questions without pretending the page replaces every table-based load study.
Can I use this electrical service size calculator for a commercial tenant or a multifamily house service?
No. This page is scoped for one dwelling unit. Commercial occupancies, mixed-use services, and multifamily house services need different load treatment and should be reviewed separately.
Why does the same dwelling load draw more amperes on 120/208V than on 120/240V?
Because amperes equal volt-amperes divided by voltage. The same VA load on a lower line-to-line voltage produces higher current, so a 120/208V dwelling usually screens at a higher service current than the same load on 120/240V.
Does this page replace the adopted NEC and local inspector review?
No. It is a planning tool only. Final service sizing still depends on the adopted NEC edition, local amendments, utility requirements, actual equipment data, and the full project scope.

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