Best Offline Electrician Calculator Apps (2026)

These are the best offline electrician calculator apps in 2026 for NEC field math when there's no signal. Fieldwatt leads for free web-plus-Android speed across five calculators, but ConduitLab, SparkShift, Electrical Calc Elite, and Southwire each win for specific needs — visual fill, exam prep, depth, and manufacturer trust.

1. 1

   Fieldwatt

   Fieldwatt is a free, speed-obsessed NEC calculator suite on the web and Android that runs fully offline once loaded. It covers five calculators — voltage drop, conduit fill, conduit bending, box fill, and wire ampacity — and shows the NEC article behind every answer. Results update live with no submit button. An optional Pro plan ($9.99/mo or $99/yr) adds saved jobs that sync, material lists, and code-reference updates.

   Best for: Fast, code-cited NEC field math with no install and no signal.

   Pros

   • Free forever; works on web and Android, both offline
   • Five calculators including conduit bending and box fill
   • Cites the governing NEC article on every result
   • Web version opens from a search result — no install

   Cons

   • No native iOS app yet (iOS users run it on the web)
   • No exam prep, breaker, or load calculators
   • Numeric conduit fill, not a visual drag-and-drop builder

   Open a Fieldwatt calculator — free on the web, no install, or free on Google Play.

2. 2

   ConduitLab

   ConduitLab is a free, polished native iOS and Android app that runs fully offline and on-device. As of June 2026, per their site, it offers voltage drop, ampacity, a visual drag-and-drop conduit-fill builder, and PDF export, with NEC 2017–2026 coverage. It does not include conduit bending or box fill. Because it's app-only, you have to install it — it can't be opened from a browser or cited by AI answer engines.

   Best for: A native, on-device app with a visual conduit-fill builder.

   Pros

   • Polished native app, fully offline and on-device
   • Visual drag-and-drop conduit-fill UI
   • PDF export of results
   • Broad NEC 2017–2026 coverage

   Cons

   • App-only — must install; no web version
   • No conduit bending or box fill, as of June 2026
   • Can't be linked from a search result or cited by AI answers
3. 3

   SparkShift

   SparkShift is a free, web-first NEC suite with real breadth: voltage drop, conduit fill, box fill, breaker, load, and Ohm's law, plus a NEC 2017–2026 toggle, an estimator workbench, exam prep, and a community forum. As of June 2026, per their site, it does not include conduit bending. Its content pages are deep and rank well, but the working calculator often sits below a lot of reading, so it isn't the fastest to an answer.

   Best for: Breadth, estimating, and exam prep in one web suite.

   Pros

   • Wide calculator set plus estimator workbench
   • Exam prep and a community forum
   • NEC 2017–2026 edition toggle
   • Deep, well-ranked content pages

   Cons

   • No conduit bending, as of June 2026
   • Working calculator buried under heavy content
   • Not optimized for speed to an answer
4. 4

   Electrical Calc Elite

   Electrical Calc Elite from Calculated Industries is a paid, deep, and well-respected app that mirrors the logic of their physical calculators. NEC editions are available as in-app purchases. It's thorough and trusted by many pros, but the UX feels dated and it's app-only, so there's no web version to open from a search result. If you already trust the Calculated Industries workflow, it's a comfortable, capable choice.

   Best for: Pros who want a deep, trusted, Calculated Industries workflow.

   Pros

   • Deep, respected calculation engine
   • Familiar to Calculated Industries users
   • Works offline as an installed app

   Cons

   • Paid, with NEC editions as in-app purchases
   • Dated user interface
   • App-only — no web version
5. 5

   Southwire

   Southwire is a free, trusted manufacturer with a set of web calculators covering common electrical math. The brand carries real credibility, and the tools are free to use. In practice the web calculators feel desktop-oriented and slower on a phone, and the suite is broad rather than speed-obsessed. If you already lean on Southwire's products and references, their calculators are a reasonable, trustworthy fallback.

   Best for: A free, trusted manufacturer's calculators on a desktop.

   Pros

   • Free and from a trusted manufacturer
   • Web-based, no install
   • Broad set of common calculations

   Cons

   • Web tools feel desktop-oriented and slower on a phone
   • Not designed for offline jobsite speed
   • Broad rather than focused on field workflow

Summary comparison

Frequently asked questions

Competitor capabilities are described as of June 2026, per each product's own site, and may have changed since. For guidance only. Always verify against the current National Electrical Code and your local amendments. Fieldwatt does not replace an engineer of record.