Wire Size Calc
NEC Ampacity & Derating
$0.99 · In‑App Purchases · Designed for iPad. Not verified for macOS.
Wire Size Calc - professional NEC calculator for electricians. Offline, permit-ready.
NEC wire size calculator for electricians, apprentices, and electrical engineers.
Determine the correct wire gauge (AWG/kcmil) for any circuit using official NEC 2023 ampacity tables and derating factors. Supports continuous and non-continuous loads, copper and aluminum conductors, 6 insulation types, and both conduit and free air installations. No internet required - works 100% offline on the job site.
FEATURES:
- Continuous and non-continuous load sizing (125% factor)
- 5 voltage presets: 120V, 208V, 240V, 277V, 480V
- Single-phase and three-phase support
- Copper and aluminum conductors: 14 AWG through 2000 kcmil
- 6 insulation types: THHN, THW, TW, XHHW-2, NM-B, USE-2
- Conduit and free air installation methods
- Temperature correction factor (NEC 310.15(B)(1))
- Conduit fill adjustment factor (NEC 310.15(C)(1))
- Termination rating check (60°C / 75°C per NEC 110.14(C))
- Overcurrent protection sizing (NEC 240.4(D))
- Optional voltage drop check when distance is provided
- PASS/FAIL indicator for quick compliance check
NEC REFERENCES:
- Table 310.16 - Ampacity in conduit/raceway
- Table 310.17 - Ampacity in free air
- Table 310.15(B)(1) - Temperature correction factors
- Table 310.15(C)(1) - Conduit fill adjustment factors
- NEC 110.14(C) - Termination temperature limits
- NEC 240.4(D) - Small conductor overcurrent protection
PRO FEATURES (one-time purchase):
- No ads
- Save calculation history
- Export calculations as PDF reports
- Dark theme support
BUILT FOR THE JOB SITE:
This app is designed by electricians, for electricians. Enter your circuit parameters, get the recommended wire size instantly - no complicated menus or unnecessary features. One-hand operation, instant results.
HOW IT WORKS:
1. Enter load current in amps
2. Select load type (continuous or non-continuous)
3. Choose voltage, phase, conductor material, insulation type
4. Set installation method and ambient temperature
5. Get recommended wire size with full derating breakdown
The calculator automatically applies:
- 125% continuous load factor
- Temperature correction for ambient conditions
- Conduit fill adjustment for conductor count
- Termination temperature limit verification
- Standard breaker size selection
PERFECT FOR:
- Licensed electricians
- Electrical apprentices
- Electrical engineers and designers
- Electrical contractors
- NEC code exam preparation
- Journeyman and master electrician exams
OFFLINE & PRIVACY:
- Works 100% offline - no internet needed
- No account required
- No data collection
- Your calculations stay on your device
Simplify your wire sizing on the job site.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
What's new:
• Moved to tradetools.dev — new umbrella site for all our trade calculators
• Updated support email: support@tradetools.dev
• Refreshed privacy & support pages with unified design
• Bug fixes and stability improvements
Thanks for using ElecTools! Send feedback to support@tradetools.dev.
The developer, Rizvan Adzhoian, 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 Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Identifiers
- Usage Data
- Diagnostics
Accessibility
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Information
- Seller
- Rizvan Adzhoian
- Size
- 31.3 MB
- Category
- Utilities
- Compatibility
Requires iOS 13.0 or later.
- iPhone
Requires iOS 13.0 or later. - iPad
Requires iPadOS 13.0 or later. - iPod touch
Requires iOS 13.0 or later. - Mac
Requires macOS 11.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
18+
- 18+
- Contains
Advertising
- In-App Purchases
Yes
- Pro Unlock $2.99
- Copyright
- © 2026 Rizvan Adzhoian