Ohm's Law Power Wheel Calculator

This calculator is a complete Ohm's law power wheel: enter any two of the four electrical quantities, voltage, current, resistance and power, and it works out the other two. Ohm's law and the power formula together link these four quantities so tightly that knowing any two lets you find the rest, and the power wheel is the classic diagram that captures all twelve resulting formulas in one place. It is one of the most useful tools in all of electronics and electrical work, used constantly for sizing components, checking circuits, choosing fuses and cables, and understanding how a circuit behaves. Rather than hunting for the right rearrangement each time, this tool lets you simply enter the two values you know and reads off the rest. You fill in any two of voltage in volts, current in amps, resistance in ohms, and power in watts, leaving the other two blank, and the calculator detects which pair you provided and computes the missing values using the correct relationships, including taking square roots where needed when power is combined with resistance. All four quantities are then displayed together. The results update as you type, so you can change an input and immediately see the effect across the whole set. Use it for electronics projects, electrical study, troubleshooting, or any time you need to move between volts, amps, ohms and watts. The underlying relationships are Ohm's law, voltage equals current times resistance, and the power law, power equals voltage times current, from which every other form follows. Enter exactly two values for a clean result; if you enter more or fewer the calculator will prompt you, since two known quantities are exactly what is needed to solve for the other two.

Enter exactly two of the four values. Based on Ohm's law (V = I x R) and the power law (P = V x I). Leave the two you want to find blank.