Ohm's Law Calculator

This Ohm's law calculator solves the single most important relationship in electronics, V equals I R, for whichever of voltage, current or resistance you do not know, and shows the power as well. Ohm's law says that the voltage across a component equals the current flowing through it multiplied by its resistance, which means if you know any two of the three you can always find the third. You choose what to solve for, enter the other two, and the calculator returns the answer using the standard units of volts for voltage, amperes for current and ohms for resistance. To find voltage it multiplies current by resistance; to find current it divides voltage by resistance; and to find resistance it divides voltage by current. Alongside the result it also gives the electrical power, since power equals voltage times current, measured in watts, which tells you how much energy the component uses each second and helps you size resistors, fuses and power supplies. Ohm's law is the foundation of circuit design and troubleshooting, used constantly by electricians, electronics hobbyists and engineering students to work out safe currents, choose components and diagnose faults. Remember it applies to ordinary resistive components at a steady temperature. Enter your two known values to see the result and the power straight away.