EleCalculator

Motors & Loads calculator

Electrical Load Calculator

Use this electrical load calculator as a mixed-scope preliminary load screen. Enter project type, floor area, service voltage, dwelling allowance inputs, HVAC, fixed loads, and light-commercial connected loads to compare demand kVA, service current, and the next review path. It supports dwelling-unit comparisons and conservative light-commercial connected-load checks, while narrower residential service pages remain the authority when the task is a one-dwelling service calculation.

Updated July 16, 2026

Enter project type, floor area, service voltage, dwelling allowances, HVAC, fixed loads, and light-commercial connected loads to screen preliminary demand kVA, service amps, and the next review path.

Use dwelling mode for residential allowance checks and commercial/workshop mode for conservative connected-load screening.

Enter the service and load inputs below for a project-specific demand kVA and service-current screen

Calculator Inputs

Field notes

Calculation Results

Enter values above to see calculation results

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Calculation history

Example Calculations

Use this preset: single-family dwelling service screenUse this preset to enter a 120/240V all-electric dwelling with standard allowances plus range, dryer, water heater, and HVAC.InputsProject Type: Single-family dwellingService Voltage: 120/240V single-phaseSquare Footage: 2000General Lighting: 3Small Appliance Circuits: 2Laundry Circuit: YesElectric Range: 12Electric Dryer: 5Water Heater: 4.5Hvac Load: 5Other Loads: 1.5
Use this preset: dwelling unit on 120/208V serviceUse this preset to compare a multifamily dwelling-unit input set on 120/208V service.InputsProject Type: Dwelling unit / multifamilyService Voltage: 120/208V three-phaseSquare Footage: 1200General Lighting: 3Small Appliance Circuits: 2Laundry Circuit: YesElectric Range: 8Electric Dryer: 5Hvac Load: 3Other Loads: 1
More examples. Open to review 1 additional calculation example.
Use this preset: light-commercial shellUse this preset to keep the commercial general load connected while screening service demand.InputsProject Type: Light commercialService Voltage: 277/480V three-phaseSquare Footage: 6000General Lighting: 3.5Water Heater: 6Hvac Load: 18Other Loads: 12

How to Use

How to use the electrical load calculator

  1. Select the project type. Single-family and dwelling-unit modes apply residential demand reductions; commercial and workshop modes stay conservative.
  2. Select the service voltage so the calculator can convert demand load into service current.
  3. Enter the floor area and the lighting load density. A dwelling screen commonly starts at 3 VA per square foot.
  4. For dwelling projects, enter the required small-appliance circuits, laundry allowance, and any household range or dryer loads that apply.
  5. Enter water-heater, controlling HVAC, and other fixed loads in kW.
  6. Review the total connected load, the estimated demand load, the calculated service current, and the recommended service size.

What this calculator does well

  • It quickly screens dwelling-unit service size from floor area and major household loads.
  • It shows when a 120/240V or 120/208V dwelling project is already pushing into the next service size.
  • It gives light-commercial users a conservative connected-load screen instead of pretending to run every NEC non-dwelling table.

When to use a narrower residential page instead

What this calculator does not model

  • Occupancy-specific non-dwelling lighting tables, receptacle counts, or kitchen-equipment tables.
  • Existing-installation demand studies, measured-demand methods, or utility service rules.
  • Detailed motor-feeder studies with separate largest-motor adders.

Quick reference values used by the dwelling screen

Item Modeled Basis Why It Matters
General dwelling load 100% first 3 kVA, 35% remainder Helps turn floor area plus allowance loads into a practical service screen.
Small-appliance circuits 1500 VA each Dwelling projects usually need at least two.
Laundry allowance 1500 VA Added to the general dwelling load when a laundry circuit is included.
Household range 8 kW up to 12 kW Applies only to the single-household range screen modeled by this tool.
Household dryer Nameplate or 5 kW minimum Prevents undersizing where a small nameplate is entered.

After the load calculation result

After screening service size here, use the Electrical Panel Load Calculator to check panel utilization and spare capacity, the Electrical Service Size Calculator to compare common dwelling service sizes, the Wire Size Calculator for conductor sizing, and the Breaker Sizing Calculator for overcurrent review.

Common Applications

Checking whether entered dwelling loads are trending toward the next modeled service-size review
Preliminary multifamily dwelling-unit service screening on 120/208V systems
Quick early-stage screening for light-commercial tenant or workshop loads
More applications. Open to review 2 additional use cases.
Comparing service-voltage options against the same connected load
Screening whether additional HVAC or fixed equipment is pushing the project into the next service size

Frequently Asked Questions

Can I use this as a commercial electrical load calculator?
Yes, but only as a conservative preliminary screen. Commercial and industrial modes keep the general load at 100% connected value because this tool does not model occupancy-specific non-dwelling demand tables, receptacle counts, or kitchen-equipment tables.
Why does the dwelling mode need at least two small-appliance circuits?
The dwelling workflow assumes the common U.S. residential allowance of 1500 VA per small-appliance circuit and requires at least two of them. That keeps the calculator aligned with a realistic dwelling-unit screening baseline instead of undercounting kitchen and pantry load.
Does this calculator size feeders and conductors too?
No. This page stops at demand load, service current, and a recommended service size. After that, use conductor and breaker tools to review ampacity, voltage drop, and overcurrent protection on the actual installation.
Why is the non-dwelling result sometimes higher than expected?
That is intentional. The commercial and workshop modes are conservative because they do not apply occupancy-specific demand tables. They are meant to be safe screening tools, not full permit-level non-dwelling load studies.

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