Conduit Fill: NEC Calculator
Voltage Drop & Wire Size
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Will it fit. What it loses. What you pull. NEC 2023 and 2026. Offline. One $7.99 purchase. No subscription.
Will it fit. What it loses. What you pull.
Offline field calculator for US residential and light-commercial electricians. One job carries the same wires across Fill, V-Drop, and Wire. Switch 2023 and 2026 in the header. One $7.99 purchase. No subscription, no account, no ads.
WILL IT FIT
Kitchen default is 14.8% FITS on ½" EMT with 3×#12 THHN plus a bare #12 ground. Status words stay shop talk: FITS, TIGHT, OVER. Ground uses bare area and does not upsize with the hots.
WHAT IT LOSES
Tap 20A rec. The 85 ft run goes HIGH at 4.5%. Upsize hots to #10 (2.8%). Ground stays #12. Feet are one-way, not the loop.
WHAT YOU PULL
The answer is the AWG. Put #10 on the pull because voltage drop at 85 ft, not because ampacity ran out.
WHAT PIPE
For EMT use ½". Types stay in shop order — EMT, then PVC, IMC, RMC — not ranked by fill percent.
HAND THIS TO THE INSPECTOR
One-page PDF with the job, pipe, wires, fill, voltage drop, and what you pull. Free PDFs carry a SAMPLE mark.
FREE AND UNLOCK
Free: fill on EMT and THHN, one What pipe?, one V-Drop, one saved job, 2026, SAMPLE PDF.
$7.99 once: unlimited V-Drop and What pipe?, Wire, 2023 and 2026, 50 jobs, clean PDF. Restore lives in Settings.
Works in airplane mode. Tables ship in the app.
This is a field calculator. It is not NFPA 70, not the codebook, and not AHJ approval. Verify every pull against the edition your inspector is using.
◆ Privacy
Data Not Collected. No tracking.
◆ Terms of Use
https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
◆ Support
https://conduitcalc.txyou.com/support
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The developer, 就洪 邓, 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 Collected
The developer does not collect any data from this app.
Accessibility
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Information
- Seller
- 就洪 邓
- Size
- 7 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Unlock the job $7.99
- Copyright
- © 2026 TXYOU
