Ohm's Law Calculator
Calculate voltage, current, resistance, and power from two known electrical values.
Two known values
Choose two different quantities and enter base units: volts, amps, ohms, or watts. The calculator derives the other two using Ohm's law and power relationships.
V = I × R; P = V × I
Units and limits
Convert mV, mA, kΩ, or mW to base units first. Results describe ideal mathematical relationships and do not replace measurements, component tolerances, or electrical safety rules.
Frequently asked questions
Which two values can I use?
Any two different quantities among voltage, current, resistance, and power.
Can I enter zero?
No. Implemented combinations require positive values and avoid division by zero.
Can I enter kilo-ohms?
Convert to ohms first; for example, 2 kΩ is 2000 Ω.
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