Wire and circuit
Work through voltage drop, ampacity, grounding and overcurrent protection calculations.
Built for the work in front of you
Conduit and box
Estimate conduit fill, box fill and bends from the entered dimensions.
Power tools
Use motor, transformer, phase power and Ohm’s law calculators and references.
Job history
Keep results under job labels and export a PDF where the Pro feature is available.
How it works
- Choose a wire, conduit or power calculator.
- Enter conductor, load, length or enclosure details.
- Review the assumptions and result, then save or export when available.
WireSize uses NEC oriented reference data and calculation assumptions. Verify the selected edition, conductor conditions, local amendments and final installation with a licensed professional and the authority having jurisdiction.
Privacy and purchases
Calculations work on your device. Saved content, Apple services and support correspondence are explained in the Privacy Policy. Optional paid features are offered through Apple in the app; see the current terms in the App Store purchase screen.
Questions
- Are the results valid outside the United States?
- The app uses NEC oriented references. Check the rules applicable at your site; it does not establish compliance in another jurisdiction.
- Does it design an electrical installation?
- No. Results are calculation aids and need professional review of site conditions and code requirements.
- Does it need internet?
- Calculations run on the device; Apple purchase and restore services can need a connection.