What is an electrical load calculation?

An electrical load calculation determines if your electrical panel can handle additional loads. It calculates the total electrical demand of a building to ensure the service and panel are properly sized according to NEC requirements.

Is Kopperfield's load calculator NEC compliant?

Yes. Our load calculator follows NEC 220 calculation methods and is regularly updated to comply with the latest NEC code cycle. The calculator includes both standard and optional calculation methods.

What building types can I calculate loads for?

Our load calculator supports residential dwellings (single-family and multifamily), commercial buildings, and mixed-use properties. You can calculate loads for new construction or existing buildings with additions.

Can I save and export my load calculations?

Yes. All load calculations are automatically saved to your account. You can export calculations as PDF documents suitable for permit submission and share them with your team or inspectors.

What nominal voltages are supported?

Our load calculator supports all common voltage systems: 120/240V, 120/208V, 208Y/120V 3Ø, 240V 3Ø Delta, 240V 3Ø Hi-leg Delta, 347 V 3Ø Delta, 480Y/277V 3Ø, 480V 3Ø Delta, 600Y/347 V 3Ø, and 600V 3Ø Delta.

Do you offer a free trial of the load calculator?

Yes! You can try our load calculator with a limited number of free calculations. Sign up for a free account to get started - no credit card required.

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Electrical load calculations made easy

Stop using manual spreadsheets. Now introducing an easier way to do residential and commercial electrical load calculations. Use our free tool to get accurate results with an instant PDF report that helps finish inspections and close customers faster.

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Complete accurate load calculations in minutes

Optional or standard method

Choose from either method and complete a load calc with pre-loaded common appliances and their output values

Residential and commercial calculations

Includes options to create both residential and commercial load calculations.

Calculations based on NEC rules

Utilizes default values from the 2023 National Electrical Code, Section 220, including values for EV chargers

Inspector-ready reports

Instantly generates a downloadable PDF printout of your calculation to share with inspectors or customers

Smart property data

Automatically detects location and surfaces property data including building square footage for easier calculations

Automatic demand factors

Detects and applies demand factors based on occupancy type for commercial calculations.

The Kopperfield tool helps with load calculations and avoids common mistakes, such as handling an EV charger in a load calc. I refer Kopperfield’s tool to contractors I work with.

Reina M, City Electrical Inspector

Supporting a variety of load calculation scenarios

Single family homes (standard or optional method)

Accessory dwelling units and additions

Multi dwelling units (i.e., duplex, triplex, quad)

Heat pumps

208V single phase dwellings

All common 3Ø voltages

All NEC-defined occupancy types

Batteries (coming soon)

Now Kopperfield supports commercial load calculations. Get started today and complete commercial load calcs with confidence.

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Includes home generator sizing

Estimate generator sizing to determine what size generator you need in seconds. Adjust reserve margin and voltage dip to easily determine the right generator size for any residential project.

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Kopperfield load calculation PDF with generator sizing tool

Get started with the mobile app

Download our app to create load calculations on the go using your iOS or Android phone or tablet

Load calculator demo

Hear it from a pro

See how Kevin from Bella Electric San Diego uses Kopperfield design tools to save time and close more customers.

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Unlock unlimited load calcs

Our free load calculator is limited to 2 free uses. Get more out of your load calcs when you subscribe to our paid plan.

Unlimited load calcs

Branded templates

Custom default values

Team collaboration

Historic record of all calcs

AI-powered panel photo
processing

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Kopperfield load calculation PDF with load calculation tool

Electrical load calculation in 3 easy steps
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Add property info

Enter the address of the job you’re working on and we’ll pull in the square footage to start the residential or commercial electrical load calculation.