Electrician Calc: Wire Size
Voltage drop, conduit & panel
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Size the wire and the breaker, check voltage drop and plan a whole panel on site, in seconds. NEC or IEC 60364, AWG or mm².
Size the wire and the breaker for a circuit in seconds, by NEC 310.16 or IEC 60364. The answer stays on screen while you type, voltage drop is checked and every step is shown for the inspector.
Then plan the whole panel, print the circuit directory for the door, and send the client a PDF with your business name and license number on top.
Free: Wire Size, Voltage Drop, Power & Ohm's Law, the reference tables and 3 projects with their PDF reports. Pro unlocks all 25 calculators and unlimited projects. No ads, no account.
Every calculation follows IEC 60364 (mm², meters, 230/400 V) or the NEC / NFPA 70 (AWG, feet, 120/208/240/480 V). The app picks the standard for your country, and you can switch with one tap.
WHY ELECTRICIANS USE IT
• Real tables, not rough formulas: ampacity, temperature and grouping factors, installation methods A1–E, NEC 310.16 with 75 °C terminations
• Voltage drop by the IEC 60364-5-52 Annex G method or the NEC K-factor, with reactance and power factor
• A clear PASS / FAIL verdict with load vs. capacity and drop vs. limit bars
FREE
• Wire Size: Ib ≤ In ≤ Iz with derating, then upsized for voltage drop, plus the grounding conductor (NEC 250.122 upsized with the circuit, or the IEC Table 54.2 earth conductor)
• Voltage Drop for AC and DC: volts, percent, voltage at the load, smallest size, parallel runs, motor start
• Power & Ohm's Law: kW ↔ A ↔ kVA for DC, single and three phase
• Reference: typical circuits, wire colors, ampacity tables, breaker curves, RCD types, IP codes, formulas
PRO
• Panel Planner: list the circuits and get breakers, RCD groups or RCBOs, surge protection, phase balance, diversity, main switch, a DIN-rail layout, a materials list and a printable panel directory with slot numbers (NEC 408.4)
• Wire Ampacity and Max Wire Length
• Conduit & Box Fill (NEC Chapter 9, 314.16)
• Motor Circuit: full-load and starting current, breaker, cable and overload
• Transformer & Fault Level, Ground-Fault Loop (Zs) with B/C/D trip check
• Grounding Conductor & Withstand, Ground Rod resistance
• Test Results: insulation, Zs, RCD trip times and polarity per circuit, judged to IEC 60364-6, saved to the job and the PDF
• Underfloor Heating: cable length and laying pitch or mat, thermostat, breaker and supply cable
• Load Schedule with demand factors and automatic phase balancing
• Power Factor Correction (kvar and µF)
• Solar PV Strings: Voc in frost, Vmp in heat, MPPT and input current limits
• Backup Power: inverter, LiFePO4 / AGM battery and generator for outages
• Lighting Design, Energy Cost, Battery & UPS
• AWG ↔ mm² including aluminum to copper replacement, Unit Converter
• Unlimited projects: results per job with client, address and notes, and a PDF report headed with your business name, license number and contacts
MADE FOR THE JOB
• Every result suggests the next step: wire size, then voltage drop and conduit fill
• Share any result as an image card or as text
• Dark and light themes, large clear numbers, works offline
• Back up your projects to a file and restore them on a new phone
• English, Spanish and Ukrainian
Pro is an auto-renewing subscription (yearly or monthly, as shown in the app); the yearly plan may start with a free trial. Payment is charged to your Apple ID when you confirm the purchase (when the free trial ends, if you start one). Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. You can manage or cancel your subscription in your Apple ID settings at any time.
Calculations are a design aid. Always check the final design against the regulations that apply where you work.
NEC® and NFPA 70® are registered trademarks of the National Fire Protection Association. Electrician Calc is not affiliated with or endorsed by NFPA.
Terms of Use: https://andronaft-2.github.io/app_politics_and_terms/electrician-calc/terms.html
Privacy Policy: https://andronaft-2.github.io/app_politics_and_terms/electrician-calc/privacy.html
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Back up your projects to a file and restore them on a new phone (free). NEC estimates: sales tax on materials only, with 0/6/8 % presets, also on the PDF. Wire Size warns when an upsized NM-B cable needs a larger ground (NEC 250.122(B)). Search in another language now puts the calculator you named first. Small fixes from testing.
The developer, Andrii Zhukovskyi, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Purchases
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Andrii Zhukovskyi
- Size
- 33 MB
- Category
- Utilities
- Compatibility
Requires iOS 15.0 or later.
- iPhone
Requires iOS 15.0 or later. - iPod touch
Requires iOS 15.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Pro Lifetime $49.99
- Pro Monthly $4.99
- Pro Yearly $24.99
- Copyright
- © 2026 Dre Dev