ElectroCalc is a free collection of electrical engineering calculators — no sign-up, no clutter, just the tool you need and an instant answer.
ElectroCalc started as a simple resistor color code calculator and has grown into a full toolkit covering the calculations electronics students, hobbyists, and working engineers reach for most often — Ohm's Law, wire gauge sizing, capacitor codes, LED resistors, transformer ratios, battery runtime, and more.
Every calculator runs entirely in your browser. Nothing you type is uploaded or stored — you enter values, get an answer, and move on.
ElectroCalc is supported by advertising, which keeps every calculator free to use with no account or payment required. We aim to keep ads unobtrusive and separate from the actual tools.
Formulas used across ElectroCalc are based on standard, widely-taught electrical engineering principles (Ohm's Law, EIA resistor color code standards, standard wire gauge tables, etc.). That said, for safety-critical or professional work, always verify results against a datasheet or a second reference — these tools are built for quick reference and learning, not as a substitute for professional engineering judgment.
Found a bug, have a suggestion, or want to request a new calculator? We'd like to hear from you.