Calculate voltage, current, resistance, or power using Ohm's Law formulas. Enter any two known electrical values and this calculator will solve the missing value, convert common units, and show related electrical results.
Solve for voltage:
Enter current and resistance. The calculator uses V = I × R.
Solve for current:
Enter voltage and resistance. The calculator uses I = V ÷ R.
Solve for resistance:
Enter voltage and current. The calculator uses R = V ÷ I.
Solve for power:
Enter voltage and current. The calculator uses P = V × I.
An Ohm's Law calculator helps estimate electrical values quickly when working with circuits, components, power supplies, resistors, batteries, and basic electrical planning.
It is useful for checking voltage drop, current draw, resistance needs, wattage, circuit loads, electronics projects, and simple DC electrical calculations.
Your result shows the solved electrical value, converted voltage, current, resistance, power, formula used, electrical load category, estimated current in milliamps, resistance in kilohms, power in kilowatts, and comparison scenarios.
Ohm's Law is the relationship between voltage, current, and resistance. The basic formula is voltage equals current multiplied by resistance.
Divide voltage by resistance. For example, a 12 volt circuit with 6 ohms of resistance has 2 amps of current.
Divide voltage by current. For example, a 12 volt circuit drawing 2 amps has 6 ohms of resistance.
It can provide a basic AC estimate, but real AC circuits may also involve power factor, impedance, frequency, inductance, and capacitance.