Electrical Calculators — Ohm's Law, Wiring & Solar

Electrical math is unforgiving — an undersized wire or an ignored voltage drop is a safety issue, not a rounding error. This category is being built around the calculations electricians and careful DIYers reach for most: Ohm's law in all four arrangements, voltage drop over cable runs, wire gauge selection for a given load and distance, and what an appliance actually costs to run per month.

Every tool will show the formula and its assumptions. One rule stands above all of them: calculators inform, codes govern. Wiring work must follow your local electrical code and, in most places, be done or inspected by a licensed electrician — use these to understand and plan, not to skip the professional.