Free interactive tools that calculate as you type — for students, technicians and engineers. Everything runs in your browser.
Every tool calculates instantly and explains the result — no sign-up, no waiting
Enter any two of voltage, current, resistance and power — get all four instantly.
Work out a load's kWh consumption and monthly cost — DC, single-phase or three-phase AC.
Read any resistor's value from its colour bands — 4 or 5 bands, with tolerance range and a live diagram.
Combine any number of resistors in series or parallel into one equivalent value.
Check the voltage drop along a cable and the minimum cross-section that keeps you within limits.
Output voltage of a two-resistor divider — including the effect of a load.
Size the series resistor that drives an LED safely — with the nearest standard value.
Decode a printed capacitor code (104 · 4n7 · 220) into every unit.
Read an SMD resistor from its marking — 3/4-digit, R-notation and EIA-96.
Capacitive and inductive reactance at a frequency — and the LC resonant frequency.
The −3 dB cutoff of a simple filter — and the attenuation at a frequency you pick.
The trace width a current needs per IPC-2221 — with resistance, voltage drop and dissipation.
Convert a resistor network between star (Y) and delta (Δ) connections in one step.
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Ohm's law — enter any two values and get all four