WireGaugeCalc Free calculator · NEC cited · works offline
Electrical Calculator Software Free
Electrical calculator software free is fast with WireGaugeCalc, since the calculator runs in your browser and handles wire size, voltage drop, conduit fill, box fill, and ampacity in one place.
You enter the load, run length, and conductor details, so the math comes back without flipping through tables.
That means you can size a circuit on the truck and move on to the next task.
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.
Free Electrical Math For Daily Field Work
Every tool here ties back to NEC values, so the numbers match what you would pull from the code book.
Nothing is locked behind a paywall, since the goal is to give electricians a quick check during rough-in or trim.
You get the same calculation whether you are at a panel or under a crawlspace.
What The Calculator Covers
One free toolset handles the common circuit questions you hit in a day:
- Wire size from load, distance, and termination temperature
- Voltage drop against the 3% branch-circuit guideline
- Conduit fill at the 40% limit for EMT, PVC, and RMC
- Box fill volume per NEC 314.16(B)
- Ampacity by the 60, 75, and 90 degree C columns
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
Is the electrical calculator really free?
Yes, every calculation runs at no cost and without a sign-up. You can use it on as many jobs as you need.
Does the software replace the NEC code book?
No, it speeds up the math but it does not replace the code. Always verify the result against the current NEC and your local authority having jurisdiction before final install.
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.