# OHMs Law Calc > Calculates Ohm's Law for single and three-phase electrical loads. (iPhone/iPad app by Caladan Software.) - Source: https://appshunter.io/ios/app/ohms-law-calc/id497274523 (this page in markdown: same URL + `.md`) - Developer: [Caladan Software](https://appshunter.io/developer/497274526) - Category: Reference, Productivity - Price: $1.99 - Rating: 4.00/5 from 3 App Store ratings · 8 written reviews indexed - Age rating: 4+ - Requires: iOS 15.0 · 9 MB - Languages: American English - Released: 2012-01-31 - Data updated: 2026-08-29 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/ohms-law-calc/id497274523/reviews.md ## What is OHMs Law Calc? A precision electrical calculator for electricians, engineers, students, and AV/lighting pros — built for iPhone, iPad, and Mac. Single-Phase Calculator Enter any two of Volts, Amps, Watts, or Ohms and the app solves the other two instantly. Results are displayed on a classic Ohm's Law pie chart with a live readout hub, so you can see the relationship between values at a glance. Three-Phase Calculator A spreadsheet-style grid for balanced or unbalanced three-phase loads. Enter per-leg voltage, current, or power and the app fills in the rest, including line and phase totals. Toggle between Delta and Wye/Star configurations — the math adjusts automatically. Power Factor A collapsible PF panel on both screens lets you apply any power factor from 0 to 1. Real Power, Apparent Power (VA), and Reactive Power (VAR) are calculated and clearly labeled. Your PF setting is remembered between sessions. NEC-Compliant Breaker Sizing Full Load Amps (FLA) and recommended breaker sizes are calculated automatically using NEC sizing rules, so you can spec circuits with confidence. Visualization Mode Tap Visualize from any calculation to see five live, interactive diagrams powered by your current values: Delta wiring topology Wye / Star wiring topology Bus-bar distribution view Phasor diagram with power triangle (P, Q, S, and PF angle) Dashboard — an all-in-one overview combining schematic, per-leg cards, and KPI readouts Print & Share Send any visualization straight to AirPrint as a clean, light-mode page — handy for job folders, submittals, or classroom handouts. Universal & Responsive One app, every Apple device. Optimized layouts for iPhone portrait, iPhone landscape, iPad split-view, and Mac Catalyst, with full dark-mode support and high-contrast yellow input cells for readability on the job site. Keyboard & Input Polish Tap-to-select-all on any field, a Done bar above the keyboard, and auto-scroll that keeps the focused field visible while you type. ## Key features - Single and three-phase calculations - Vector calculations for unbalanced loads - Calculate Watts, Volts, Amps, or Ohms - Back-calculate load resistance - Widget support ## Recent user reviews (8 of 8) All indexed reviews: https://appshunter.io/ios/app/ohms-law-calc/id497274523/reviews.md ### 5/5 — Quick and Easy! *2015-03-28* This app really does calculate Three Phase correctly... Not just using the old "lazy engineers" trick of multiplying by 1.732... But rather doing the actual VECTOR MATH to properly calculate BOTH balanced and unbalanced loads. Works great for resistive AC circuits too! The app does exactly what it says, makes single and three phase calculations a breeze. I'll never get the wrong Three Phase Breaker again! ### 2/5 — Incorrectly calculates for AC *2015-03-22* Good attempt, but this calculator works 100% correctly ONLY for DC. For AC, it ignores Power Factor (PF), caused by ever present out-of-phase Reactive currents. All AC "Power" results are really in "Volt-Amps" (VA) not Watts. For 3-Ph AC it incorrectly calculates VA, when given Voltage & Current. The correct method is: V x A x 1.73 (Sq Root of 3) = VA Power in Watts is then: VA x PF = Watts PF is always a number between 0 & 1, with 1 being in-phase (purely resistive) current, and 0 being 90 deg out-of-phase (purely reactive) current. For calculations (where actual PF is unknown) a PF of 0.8 is typically used. Resistance alone in never the only factor in AC Circuits. ### 1/5 — Sparky *2012-09-01* A lot of better free apps out there! Waste of money! Wish I can take my Money back. ### 5/5 — Best ohms law app I have ever used! *2012-04-24* This is the best ohms law app I have in my electronics folder! I really like this app! Good job!A+ ### 5/5 — awesome *2012-03-03* works just like described, it does 3phase and single phase. It's also iphone and ipad compatible. 5 start app all the way ### 5/5 — Draftmen *2012-02-28* This is a very good calculator one of the best I have ever used . Very well done. ### 5/5 — Wow. *2012-02-09* 3 Phase works!!! Finally an app with 3 phase that works. Great app, highly recommended. Very easy to use UI, saves a lot of time and mistakes. Helpful guide provided on website as well. A must have. ### 5/5 — 3 Phase Values At Last! *2012-01-31* Great app. The only app that I've found that properly calculates 3 phase values. ## Frequently asked questions about OHMs Law Calc ### What is OHMs Law Calc? OHMs Law Calc is a paid application that calculates Ohm's Law for single and three-phase electrical applications. It uses vector calculations for both balanced and unbalanced loads, allowing users to quickly determine Watts, Volts, Amps, or Ohms. ### Does OHMs Law Calc have ads? No, OHMs Law Calc does not contain advertisements. It is a paid application available for $1.99. ### What devices is OHMs Law Calc compatible with? OHMs Law Calc is compatible with iPhone, iPad, and iPod devices. It is suitable for users aged 4 and above. ### How often is OHMs Law Calc updated? The latest version of OHMs Law Calc, version 2.1, was last updated on October 24, 2023. Updates are released periodically to improve functionality and address any issues. ### What is the user rating for OHMs Law Calc? OHMs Law Calc has a user rating of 3.7 stars based on 3 ratings. This indicates a generally positive reception from its user base. ### Can OHMs Law Calc calculate unbalanced three-phase loads? Yes, OHMs Law Calc specifically uses proper vector calculations to accurately compute both balanced and unbalanced three-phase loads. This feature is crucial for complex electrical system analysis. ### Does OHMs Law Calc offer a free trial? OHMs Law Calc is a paid application and does not offer a free trial. It is available for a one-time purchase price of $1.99. ### What electrical parameters can OHMs Law Calc calculate? OHMs Law Calc can easily and quickly calculate Watts, Volts, Amps, or Ohms. It also allows users to back-calculate the Load resistance from voltage and Phase Amps. ## Version history (last 5 releases) ### 3.3.3 — 2026-06-07 APPLE WATCH SUPPORT! Plus three phase total watt entry with back calculation added ### 3.0.0 — 2026-05-11 What's New in 3.0 A full ground-up refresh of OHM's Law Calculator, rebuilt for modern iPhone, iPad, and Mac. Redesigned single-phase calculator — enlarged Ohm's Law pie chart with a clean inner hub, four pinned input fields, and live recalculation as you type. Spreadsheet-style three-phase grid — enter per-leg values in a clear tabular layout, with totals that fit on screen in both portrait and landscape. Delta and Wye topology toggle — switch between three-phase configurations with the math handled correctly for each. Power Factor support — collapsible PF disclosure on both single- and three-phase screens, with the Watts row labeled with the active PF (e.g. "Real Power (PF @ 0.85)"). Your PF setting persists across launches. Visualization mode — five interactive diagrams accessible from any calculation: Delta, Wye/Star, Bus-bar, Phasor (power triangle), and a full Dashboard view. Print from visualization — send any diagram straight to AirPrint, optimized for light-mode output. NEC-compliant breaker sizing — automatic, code-aware breaker recommendations. Truly universal layout — side-by-side landscape views, responsive iPad and Mac Catalyst scaling, and rotation through every orientation. Keyboard polish — Done bar, tap-to-select-all, and the focused field auto-scrolls above the keyboard. Dark mode throughout, with high-contrast yellow input cells for readability in the field. ### 2.1 — 2023-10-24 New version adds support for additional devices and resolvers some on screen keyboard issues ### 1.51 — 2015-03-21 This app has been updated by Apple to display the Apple Watch app icon. Adjusts visuals to be more like iOS 8 ### 1.5 — 2014-10-10 New Version adds support for Widgets! Now you can add OHM's Law Calc to the Notifications area in the Today view. Access a "Quick LAW" version right from the lock screen on ANY iOS device! Now calculating Volts, Amps and Watts is even quicker and more convenient! ## More apps by Caladan Software - [Mila UI](https://appshunter.io/ios/app/mila-ui/id1216345445) - [Heating Element Calculator](https://appshunter.io/ios/app/heating-element-calculator/id1227516847) All apps by Caladan Software: https://appshunter.io/developer/497274526 ## Related topics [ohms law calc](https://appshunter.io/ios/topics/ohms-law-calc) · [the power law calc](https://appshunter.io/ios/topics/the-power-law-calc) · [the ohms law calc](https://appshunter.io/ios/topics/the-ohms-law-calc) · [ohms](https://appshunter.io/ios/topics/ohms) --- *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 2026-08-29.*