Fieldwatt vs SparkShift
Fieldwatt and SparkShift are both free, web-first NEC calculator suites. Fieldwatt is faster and adds conduit bending, working fully offline with the NEC article shown on every answer. SparkShift covers more ground — breaker and load math, an estimator workbench, and exam prep — but buries the working calculator under heavy content.
| Feature | Fieldwatt | SparkShift |
|---|---|---|
| Price | Free forever; optional Pro $9.99/mo or $99/yr | Free (as of June 2026, per their site) |
| Platforms | Web + Android, both fully offline | Web-first (as of June 2026, per their site) |
| Voltage drop, conduit fill, box fill | Yes | Yes |
| Conduit bending (offsets, shrink, 90° stub) | Yes | No, as of June 2026 |
| Wire ampacity (NEC 310.16) | Yes | Yes (load + breaker tools) |
| Breaker & load calculators, Ohm's law | Not yet | Yes, as of June 2026, per their site |
| Estimator workbench | Material lists (Pro) | Yes — fuller estimator, as of June 2026 |
| Exam prep & community forum | No | Yes, as of June 2026, per their site |
| NEC edition toggle (2017–2026) | NEC 2023; code-reference updates (Pro) | 2017–2026 toggle, as of June 2026 |
| Shows the NEC article behind every answer | Yes, on every result | Cited within content pages |
| Speed to an answer | Calculator loads first; live results, no submit | Working calc sits below long content |
The honest verdict
If you want depth — breaker and load math, an estimator workbench, exam prep, and a content library — SparkShift is the stronger pick, and it already ranks well for a reason. If you want to open a page and get a code-cited answer in seconds, including conduit bending, with everything working offline on the jobsite, Fieldwatt is built for that. Many electricians will reasonably keep both: SparkShift for study and estimating, Fieldwatt for fast field math.
Free to use on the web — no install, works offline — or take it with you on Android:
Frequently asked questions
Is Fieldwatt free like SparkShift?
Yes. Fieldwatt's five NEC calculators are free forever on web and Android. An optional Pro plan ($9.99/mo or $99/yr) adds saved jobs that sync, material lists, and code-reference updates. SparkShift is also free as of June 2026, per their site.
Does SparkShift have a conduit bending calculator?
Not as of June 2026, per their site. SparkShift covers voltage drop, conduit fill, box fill, breaker, load, and Ohm's law. Fieldwatt adds conduit bending — offsets, shrink, and 90° stub take-up — alongside the same core NEC calculators.
Which is better for exam prep?
SparkShift. It includes dedicated exam prep and a community forum, which Fieldwatt does not. Fieldwatt is focused on fast field calculations rather than study material, so for journeyman or master exam prep, SparkShift is the better fit.
Which loads faster on a jobsite?
Fieldwatt is built speed-first — the calculator loads before anything else, results update live as you type, and it runs fully offline once loaded. SparkShift's calculators are accurate but sit below content-heavy pages, so they take longer to reach.
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.