# Mike Holt's Electrical Toolbox — Electrical Power Calculator > Electrical calculation tool for conductor, circuit protection, race, and grounding conductor sizing. (iPhone/iPad app by Mike Holt Enterprises.) - Source: https://appshunter.io/ios/app/mike-holts-electrical-toolbox/id1406630647 (this page in markdown: same URL + `.md`) - Developer: [Mike Holt Enterprises](https://appshunter.io/developer/1349960186) - Category: Utilities, Education - Price: Free - Rating: 4.60/5 from 197 App Store ratings · 30 written reviews indexed - Age rating: 4+ - Requires: iOS 14.0 · 26 MB - Languages: American English - Released: 2019-05-23 - Data updated: 2026-08-10 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/mike-holts-electrical-toolbox/id1406630647/reviews.md ## What is Mike Holt's Electrical Toolbox? Mike Holt, the industry leader in the electrical industry (MikeHolt.com) has created an amazing, practical and useful app for the electrician, inspector, instructor, contractor and engineer. The app contains conductor sizing (including voltage drop limitations), circuit protection sizing, race sizing, equipment grounding conductor sizing for electric heating equipment (commercial and Residential), air-conditioning equipment (commercial and Residential), motors (commercial and Residential), Transformers (commercial) , and dwelling-unit service calculations and sizing. ## Key features - Conductor sizing - Voltage drop limitations - Circuit protection sizing - Race sizing - Equipment grounding conductor sizing - Dwelling-unit service calculations ## Recent user reviews (10 of 30) All indexed reviews: https://appshunter.io/ios/app/mike-holts-electrical-toolbox/id1406630647/reviews.md ### 1/5 — You can’t email the information you have to forward *2025-10-22, version 1.0.39* It’s a good app, but it has the option to email the results, but it won’t let you. It’s frustrating. ### 3/5 — Need more *2025-03-11, version 1.0.36* Take transformers at least to 225kva. 112 isn’t enough for this to be useful. ### 5/5 — Great app *2024-10-05, version 1.0.34* Perfect app. I really like how it gives the code article with the results. ### 5/5 — Great in the tool box *2024-09-13, version 1.0.34* Outstanding app to verify calculations. The best parts is it gives reference to code sections so you ca read for your self. ### 1/5 — Outdated *2024-06-26, version 1.0.34* Info in this app is outdated and for the most part useless to any decent electrician ### 5/5 — Awesome tool *2024-03-26* Absolutely essential for on the spot reference. Incredible. Thanks so much. ### 3/5 — This guy wrote your textbook *2024-03-14, version 1.0.34* If you don't know who this guy is, you likely read his textbook. On his TV show, Holt plays a gameshow host, and throws topics at residential, commercial, and government tier electricians. The government guy always has to code, infinite budget. And as you go down tiers you learn how the budgeted tiers deal with it. ### 4/5 — What version of the nec is this using ? *2024-02-23, version 1.0.34* Seems useful but load calc a little clunky ### 5/5 — Rodriguez Electrical Contractor *2023-08-11, version 1.0.30* Excelente tool for the field. ### 5/5 — Great Jobsite Resource *2023-05-29, version 1.0.30* This app is a great resource for the industry! ## Frequently asked questions about Mike Holt's Electrical Toolbox ### What kind of calculations does this app perform? This app performs a variety of essential electrical calculations. These include conductor sizing, accounting for voltage drop limitations, circuit protection sizing, race sizing, and equipment grounding conductor sizing for various types of equipment like heating, air-conditioning, motors, and transformers. It also handles dwelling-unit service calculations. ### Who is this app designed for? The app is specifically designed for professionals in the electrical industry. This includes electricians, inspectors, instructors, contractors, and engineers who need practical and useful tools for their daily work. ### Is this app free to use? Yes, based on the provided information, this app is available for free. There are no indications of in-app purchases or advertisements, suggesting a completely free user experience. ### What types of electrical equipment can be calculated? The app supports calculations for a wide range of electrical equipment. This includes electric heating equipment (commercial and residential), air-conditioning equipment (commercial and residential), motors (commercial and residential), and transformers (commercial). It also covers dwelling-unit service calculations. ## Version history (last 5 releases) ### 2.0.03 — 2026-07-09 Bug fixes and performance improvements. ### 2.0.02 — 2026-06-26 Bug fixes and performance improvements. ### 2.0.01 — 2026-06-10 Bug fixes and performance improvements. ### 1.0.39 — 2025-10-13 Bug fixes and performance improvements. ### 1.0.38 — 2025-05-14 Bug fixes and performance improvements. ## Apps similar to Mike Holt's Electrical Toolbox | App | Rating | Price | Category | | --- | --- | --- | --- | | [Electrical Calculator lite](https://appshunter.io/ios/app/electrical-calculator-lite/id922903696) | 4.6 (570) | Free | Utilities | | [Electrical Calc Elite](https://appshunter.io/ios/app/electrical-calc-elite/id510284903) | 4.7 (124) | $19.99 | Utilities | | [Elektrische Rechner](https://appshunter.io/ios/app/elektrische-rechner/id495478153) | 4.6 (462) | $3.99 | Utilities | | [Electric Toolkit - Calculator](https://appshunter.io/ios/app/electric-toolkit-calculator/id516862639) | 4.8 (288) | $5.99 | Utilities | | [Rule of Three Calculator](https://appshunter.io/ios/app/rule-of-three-calculator/id1185318300) | 2.3 (4) | Free | Utilities | | [小灵龙App](https://appshunter.io/ios/app/app/id1221738240) | 1.0 (12) | Free | Utilities | ## Related topics [transformers electrical](https://appshunter.io/ios/topics/transformers-electrical) · [electrical load calculator](https://appshunter.io/ios/topics/electrical-load-calculator) · [mike holt](https://appshunter.io/ios/topics/mike-holt) · [mike holt enterprises](https://appshunter.io/ios/topics/mike-holt-enterprises) · [electrical calculations](https://appshunter.io/ios/topics/electrical-calculations) · [nfpa 70](https://appshunter.io/ios/topics/nfpa-70) · [fault current calculator](https://appshunter.io/ios/topics/fault-current-calculator) · [nfpa link](https://appshunter.io/ios/topics/nfpa-link) · [uglys](https://appshunter.io/ios/topics/uglys) · [nec code book](https://appshunter.io/ios/topics/nec-code-book) · [electricians bible](https://appshunter.io/ios/topics/electricians-bible) · [ideal electrical](https://appshunter.io/ios/topics/ideal-electrical) · [electrical troubleshooting](https://appshunter.io/ios/topics/electrical-troubleshooting) · [uglys electrical](https://appshunter.io/ios/topics/uglys-electrical) · [wire sizing](https://appshunter.io/ios/topics/wire-sizing) · [electrical workers 22 fcu](https://appshunter.io/ios/topics/electrical-workers-22-fcu) · [elliott electric supply](https://appshunter.io/ios/topics/elliott-electric-supply) · [elliott electric](https://appshunter.io/ios/topics/elliott-electric) · [captain code nec code changes](https://appshunter.io/ios/topics/captain-code-nec-code-changes) · [national electrical code](https://appshunter.io/ios/topics/national-electrical-code) --- *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 2026-08-10.*