Engineering Calculators

Electrical, electronics, industrial automation and thermodynamics tools — built by an engineer, with every formula and reference standard shown.

LED Resistor Calculator — solve for Vsupply, Vf, forward current or R from the other three

Ohm's Law Calculator — solve for V, I, R or P from any two known values

Resistor Color Code Calculator — decode band colors to resistance, or look up colors for a value

Series & Parallel Resistor Calculator — equivalent resistance for 2 or 3 resistors, with a merge animation

Voltage Divider Calculator — solve for Vin, R1, R2 or Vout from the other three