WireGaugeCalc Free calculator · NEC cited · works offline
Slove For Ampacity
Slove for ampacity is quick with WireGaugeCalc, since you pick the conductor and the calculator reads the rated current straight from the NEC table.
It pulls the value from the 60, 75, or 90 degree C column for copper or aluminum, so the number reflects the temperature column you are allowed to use.
You see the ampacity at a glance and can confirm a conductor is large enough for the breaker.
Open the calculatorAllowable ampacity from NEC Table 310.16 at the chosen termination temperature. Field aid only, verify against the current NEC and your local authority having jurisdiction.
Read Ampacity From The Right Temperature Column
The calculator shows ampacity per the termination rating, since your lugs and devices cap which column applies under NEC 110.14(C).
It also applies ambient and bundling adjustment factors, so the corrected ampacity reflects real conditions in the raceway.
Inputs That Set The Ampacity Value
The ampacity result depends on these choices:
- Conductor size in AWG or kcmil
- Copper or aluminum conductor material
- Termination column: 60, 75, or 90 degrees C
- Ambient temperature for the correction factor
- Number of current-carrying conductors for adjustment
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
Can I use the 90 degree column for my final ampacity?
You can use it only for derating math, not for the final rating, since terminations are usually limited to 60 or 75 degrees. The lowest-rated termination still governs the usable value.
How do ambient and conductor count affect ampacity?
Higher ambient temperature and more current-carrying conductors both lower the corrected ampacity. Always verify the adjusted figure 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.