Conduit Fill Calculator

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Content rating
Everyone
1+
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Content rating
Everyone
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About this app

Conduit Fill Calculator checks whether a conductor bundle fits a raceway, or finds the smallest trade size that will hold it, against NEC Chapter 9 tables.

Use this conduit fill calculator to check fill percentage for EMT, IMC, RMC, or PVC raceway, or to find the minimum trade size for a bundle of conductors, using NEC Chapter 9 Table 1, Table 4, and Table 5 data. Every area figure applied to your bundle is shown on screen so you can check the math.

FILL
- Pick a raceway type and trade size, and toggle the Note 4 nipple exception for a raceway 24 inches or less
- Build a mixed conductor bundle: add rows of insulation type, conductor size, and quantity
- See fill percentage against the applicable limit as you edit, with a gauge showing where you sit against the 53%/31%/40%/60% bands
- See total conductor area, allowed area, and conduit total area
- Save the current bundle and raceway as a pull; the first saved pull needs no ad

CONDUIT
- Enter a conductor bundle and get the smallest verified trade size of the selected raceway type that stays within the NEC Chapter 9, Table 1 fill limit
- See the next trade size up as headroom for a run that may be pulled again
- Review the saved bundle summary with one tap back to editing it
- View your saved pulls; saving needs no ad, and the list unlocks with a short rewarded ad

PULLS
- Save a named raceway-and-bundle combination for repeat use
- Reload a saved bundle into the Fill screen in one tap
- Delete any saved bundle
- The first saved bundle needs no ad; saving more unlocks with a short rewarded ad

WHAT IT CALCULATES
This app implements NEC Chapter 9 Table 1 fill-limit percentages (which depend on conductor count, not on how full the raceway looks), Table 4 conduit interior areas for EMT, IMC, RMC, and PVC Schedule 40/80, and Table 5 conductor areas for THHN/THWN-2, XHHW-2, and TW insulation. It is a calculation aid, not a substitute for the authority having jurisdiction or the code edition actually adopted for an installation, which governs.

BUILT FOR THE JOB SITE
- Fast entry with minimal taps
- Works offline on site
- No account required
- Your saved pulls and bundles stay on your device

This app is ad-supported. Fill and sizing calculations are always available; saving beyond the first pull or bundle unlocks with a short rewarded ad.
NEC Chapter 9 raceway fill percentage and minimum conduit size.
Updated on
Aug 16, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • This app may share these data types with third parties
    Device or other IDs
  • No data collected
    Learn more about how developers declare collection
  • Data is encrypted in transit
  • Data can’t be deleted

What’s new

First release.

List the conductors in a run and the app shows fill percentage for EMT, IMC, RMC, or PVC, or the smallest trade size that holds them.

The Chapter 9 areas behind each answer are shown on screen.
Content rating
Everyone
Learn more

App support

Phone number
+16317729105
About the developer
K4Y APPS LLC
hello@k4yapp.com
418 Broadway Ste N Albany, NY 12207-2922 United States
+1 631-772-9105

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