# FILL ◦ Conduit Fill Calculator — NEC 2026 & 2023 Wire Sizing

> NEC 2023 conduit fill calculator for electricians, offering fast and accurate calculations. (iPhone/iPad app by James McKinney.)

- Source: https://appshunter.io/ios/app/fill-conduit-fill-calculator/id6760678246 (this page in markdown: same URL + `.md`)
- Developer: [James McKinney](https://appshunter.io/developer/1855741871)
- Category: Utilities, Reference
- Price: Free with in-app purchases
- Rating: 4.00/5 from 3 App Store ratings · 1 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.1 · 37 MB
- Languages: American English
- Released: 2026-03-20
- Data updated: 2026-08-19
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/fill-conduit-fill-calculator/id6760678246/reviews.md

## What is FILL ◦ Conduit Fill Calculator?

The conduit fill calculator electricians actually reach for on the job.

Now built for both NEC 2026 and NEC 2023. Same verified fill tables, switch editions in a tap, work to whichever code your inspector goes by.

Enter your wires, pick your conduit, get your fill percentage. That's the whole app.

FAST, ACCURATE NEC CALCULATIONS
Based on NEC Chapter 9, Tables 1, 4, and 5. Every number matches the published tables, and you can check the math yourself. NEC 2026 and 2023 use the same fill values, so the answer is right either way.

FORWARD & REVERSE
Forward: "Will these wires fit in this conduit?"
Reverse: "What's the smallest conduit for these wires?"
Reverse mode ranks every conduit type by fill percentage and highlights the smallest compliant size.

HOW IT WORKS
- Select conduit type and size
- Add conductors by type, gauge, and quantity
- See fill percentage, wire area, and conduit area update as you go
- Green, yellow, or red tells you at a glance whether you pass

CONDUIT TYPES
EMT, RMC, IMC, FMC, LFMC, PVC Schedule 40, and PVC Schedule 80.

WIRE TYPES
THHN/THWN-2, XHHW, RHH/RHW, and THWN from 14 AWG through 2000 kcmil, plus TFN/TFFN fixture wire in 16 and 18 AWG for controls and low-voltage lighting work.

NIPPLE CALCULATIONS
Flip on nipple mode for runs 24 inches or shorter and FILL applies the 60% fill allowance from NEC Chapter 9, Table 1, Note 4.

CALCULATION HISTORY
Every calculation saves on its own. Group them by area of the job, like "Panel Room" or "3rd Floor," label them, and tap any saved entry to load it back instantly.

EXPORT & SHARE
Copy or share any calculation as clean, formatted text. Good for documentation, inspection prep, or sending to your foreman.

BUILT FOR THE TRADE
No ads. No tracking. No subscription. FILL was made by someone who gets that an electrician needs a tool that works fast and then gets out of the way. Big tap targets, high contrast, nothing you have to dig through.

TRY IT FIRST
Run 5 complete calculations free. No account, no sign-up. See how it works before you spend anything.

PRO UPGRADE ($7.99, ONE TIME)
- Unlimited calculations
- All 7 conduit types
- Calculation history with area grouping
- Export and share
- Buy once, keep it for good. No subscription.

Based on the NEC 2023 and NEC 2026 editions. NEC is a registered trademark of the National Fire Protection Association (NFPA). This app is not affiliated with, endorsed by, or sponsored by NFPA. Calculations are provided for reference and should be verified against the published NEC tables.

Privacy Policy: https://jamesmckinney.xyz/fill/privacy
Terms of Use: https://jamesmckinney.xyz/fill/terms

## Key features

- NEC 2023 compliant calculations
- Forward and reverse calculation modes
- Real-time fill percentage status
- Supports multiple conduit and wire types
- Nipple calculation mode
- Calculation history with job site grouping
- Export and share results

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| FILL Pro | $9.99 | one-time |


## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/fill-conduit-fill-calculator/id6760678246/reviews.md

### 5/5 — Awesome!

*2026-07-07*

Great tool, quick and easy to use. Love it

**Developer response:** Thanks a lot for the review!! That helps me out a ton. Feel free to reach out to me if you have any questions - james@jamesmckinney.xyz

## Frequently asked questions about FILL ◦ Conduit Fill Calculator

### How many calculations can I do for free with FILL?

You can perform 3 complete calculations for free without any sign-up. This allows you to test the app's functionality before purchasing the Pro upgrade.

### What is the cost of the Pro upgrade for FILL?

The Pro upgrade for FILL is a one-time purchase of $9.99. This unlocks unlimited calculations, all conduit types, calculation history, and export features permanently.

### Does FILL have ads?

No, FILL is designed without advertisements. The developer states it is built for the trade and aims to be a clutter-free tool.

### What NEC edition does FILL use?

FILL is based on the NEC® 2023 Edition. It uses Chapter 9, Tables 1, 4, and 5 for its calculations.

### Can I save my calculations in FILL?

Yes, every calculation in FILL auto-saves and can be organized by job site area. You can easily reload saved entries for quick reference.

### What devices is FILL available on?

FILL is currently available for iPhone and iPod devices. It is designed for mobile use in the field.

### How often is FILL updated?

The latest version, 1.0.9, was released on June 17, 2026. Updates are provided to ensure the app remains current with relevant standards and features.

### Can I share my conduit fill calculations from FILL?

Yes, the Pro version of FILL allows you to copy or share your fill calculations as formatted text. This is useful for documentation, inspection preparation, or sending results to others.

## Version history (last 5 releases)

### 1.2.0 — 2026-07-30

FIXED: Deleting one saved calculation.

Swiping a row in History used to throw you back to the calculator, so Clear All History was the only thing that worked. Now swipe left, tap DELETE, and just that one entry is gone. Swiping also closes any row you left open, and tapping an open row closes it instead of reloading it.

NEW: Email Support, in Settings.

It opens your mail app already addressed to me, with your version, build and phone details filled in. If FILL gets something wrong, or you need something it does not do yet, that button is the fastest way to tell me. Settings now shows your exact version and build too.

### 1.1.0 — 2026-07-07

NEW: NEC 2026 support. FILL now works with both the NEC 2026 and NEC 2023 editions — pick your edition in Settings and every calculation and export is labeled to match.

NEW: TFN/TFFN fixture wire in 16 and 18 AWG, for controls and low-voltage lighting conduit runs.

Also: a review prompt you'll only ever see once, and small fixes to keep FILL quick and dependable in the field.

### 1.0.9 — 2026-06-17

New: Tap NEW at the top to clear your wires and start a fresh calculation in one tap. No more deleting them one at a time.

Plus some under-the-hood fixes to keep FILL fast and reliable.

### 1.0.8 — 2026-04-22

Counter now shows free calculations remaining from first use
Added upgrade option in settings
Fixed App Store review button
Adjusted trial and review thresholds
Fixed analytics tracking

### 1.0.7 — 2026-04-04

Added prompt to review app after 10th calculation

## More apps by James McKinney

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All apps by James McKinney: https://appshunter.io/developer/1855741871

## Related topics

[conduit fill calculator](https://appshunter.io/ios/topics/conduit-fill-calculator) · [electrical conduit fill](https://appshunter.io/ios/topics/electrical-conduit-fill) · [prysmian group conduit fill](https://appshunter.io/ios/topics/prysmian-group-conduit-fill) · [conduit fill](https://appshunter.io/ios/topics/conduit-fill) · [conduit fill capacity calculator](https://appshunter.io/ios/topics/conduit-fill-capacity-calculator) · [southwire conduit fill](https://appshunter.io/ios/topics/southwire-conduit-fill)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-19.*