WireGaugeCalc Free calculator · NEC cited · works offline
Electric Load Calculator
Electric load calculator is fast with WireGaugeCalc, since you enter square footage and appliances and it totals the demand.
The tool applies the NEC demand factors, so the general lighting and appliance loads are not just added at full value.
You get an estimated service size in amps to check against the panel you plan to install.
Open the calculatorEnter any two values and read the rest.
Ohm’s law: V = I × R and P = V × I. Field aid only, verify against the current NEC and your local authority having jurisdiction.
Load Calc Electrical Demand, Done By The Numbers
General lighting is figured at 3 VA per square foot, so the calculator scales that load to the dwelling size you enter.
Large appliances and the range get their own demand factors, since the code does not expect every load to run at once.
The result divides total VA by the system voltage to give the service amperage you need.
Electrical Load Calculator Inputs For A Dwelling
Provide the loads that drive the service size:
- Square footage for general lighting
- Small appliance and laundry circuits
- Electric range or cooktop
- Water heater and dryer
- HVAC heating or cooling load
- Total amps for the service load calc electrical sizing
One app for every NEC calculation
WireGaugeCalc keeps the calculations you reach for most in one place:
- Voltage drop and wire sizing for any run
- Conduit fill for EMT, PVC, and RMC
- Box fill and junction box sizing
- Ampacity and temperature derating
- Motor circuit and load calculations
- Conduit bend offsets and saddles
Built for the field, works offline
The whole app runs on your phone, so it keeps working in a basement, an attic, or a job site with no signal.
There is no account to create and nothing to load. Open it, run the number, and get back to work.
- No signup and no signal needed
- Answers in a tap, not a spreadsheet
- Same tool on phone, tablet, and desktop
Every result cites the NEC article
Each answer shows the table or formula it came from, so you can check the method and learn the code as you go.
That makes the app useful on the job and during exam prep, since the reasoning is right next to the number.
Switch the code year your job runs on
Jurisdictions adopt the NEC at different times, so you can match the calculation to the code in force:
- NEC 2017, 2020, and 2023 tables
- Copper and aluminum conductors
- 60, 75, and 90 degree C terminations
- Single-phase and three-phase systems
Run the number, then get back to work
Stop flipping through a paper book or hopping between calculator sites. Enter your values, read the code-cited answer, and move on. Free to use, no signup.
Open the calculatorFrequently asked questions
What demand factors does the electrical load calculator use?
It applies the standard NEC demand factors for general lighting, appliances, and the range, so the total is lower than a straight sum. Confirm the method and any optional calculation against the current NEC and your local authority having jurisdiction.
Can a load calc electrical result tell me if 100 or 200 amp service fits?
Yes, the calculator gives total amps so you can compare it to a 100 or 200 amp panel. If the number lands near a limit, leave headroom for future loads.
Is WireGaugeCalc free to use?
Yes. Every calculator is free to run with no signup. A paid tier adds saved projects, PDF reports, and extra code years, but the core math stays free.
Does it work without internet?
Yes. The app runs on your device, so it keeps working with no signal on a job site, in a basement, or in an attic.
Are the results code accurate?
Results follow published NEC tables and standard formulas, and each answer shows the article it came from. It is a field aid, not a stamp of approval, so verify against the current code and your local authority before you wire anything.
Which NEC code year does it use?
You can switch between NEC 2017, 2020, and 2023, since jurisdictions adopt the code at different times. Pick the year your job runs on.