WireGaugeCalc Free calculator · NEC cited · works offline
Electrical Residential Online Load Calculater
Electrical residential online load calculater is quick to run with WireGaugeCalc.
Enter the square footage, appliances, and fixed loads, and it totals the volt-amperes using the dwelling method in NEC Article 220.
You get the calculated service size so you can pick the right panel and conductors.
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.
How The Online Electrical Load Calculation Works
General lighting starts from the floor area, since NEC 220.12 assigns volt-amperes per square foot for dwellings.
The online electrical load calculation then adds small appliance circuits, laundry, and fixed appliances before applying the demand factors.
Because the result is in amperes, you can match it directly to a service size and panel rating.
What Feeds The Online Electrical Load Calculation
Give the calculator the dwelling details and it builds the total:
- Living area square footage for general lighting
- Two small appliance circuits and one laundry circuit
- Range, dryer, water heater, and HVAC loads
- Applied demand factors from Article 220
- Total volt-amperes converted to service amps
- Suggested service size at 120/240 volts
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 service size does a typical house need?
Many single-family dwellings calculate out to a 100 or 200 amp service depending on the loads. Run the numbers for the specific home rather than assuming, and verify the result against the current NEC and your local authority having jurisdiction.
Does the calculator use the standard or optional dwelling method?
It follows the standard Article 220 method by default, adding loads and applying demand factors. The optional method in 220.82 can give a different result, so check which one your jurisdiction expects.
Should I include future loads in the calculation?
Add any known fixed loads like an EV charger or hot tub so the service has capacity. Leaving them out can undersize the panel and force an upgrade later.
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.