OHMs Law Calc

New Apple Watch Support Added!

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.