WireGaugeCalc Free calculator · NEC cited · works offline
Diameter Of A Wire Cal
Diameter of a wire cal is fast with WireGaugeCalc, since it links the AWG number to the conductor diameter for you.
You enter the gauge or the measured diameter, and the calculator returns the matching value plus a size suited to the amps and run.
That way you stop guessing at gauge in the field and pick a wire that carries the load safely.
Open the calculatorSmallest conductor whose ampacity meets the load, NEC Table 310.16. Field aid only, verify against the current NEC and your local authority having jurisdiction.
Match Wire Gauge To Conductor Diameter
Each AWG step changes the diameter by a fixed ratio, so a smaller number means a thicker conductor and more current.
WireGaugeCalc reads your gauge and shows the diameter, then checks the size against NEC 310.16 ampacity for the conductor material.
Since copper carries more current than aluminum at the same diameter, the tool flags the metal you select.
Size A Conductor From Its Diameter
The calculator turns a diameter reading into a usable wire size by checking these points:
- AWG number tied to the conductor diameter you enter
- Copper or aluminum, since the metal sets the ampacity
- Termination temperature rating, 60C, 75C, or 90C
- Load amps the run must carry
- Ampacity from the NEC 310.16 column for that material
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
Does a larger AWG number mean a thicker wire?
No, the AWG scale runs backward, so a larger number is a thinner conductor. A 12 AWG wire is thinner than a 10 AWG wire and carries less current.
Can I size a wire from a diameter measurement alone?
Diameter gives you the gauge, but ampacity also depends on the metal and the termination temperature column. Verify the final size against the current NEC and your local authority having jurisdiction.
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.