About Ohms Law Calculator

Solve for voltage, current, resistance, or power using Ohm’s Law and the power equations. Enter any two of the four values (V, I, R, P) and the calculator derives the remaining two, showing the step-by-step formula used. A second tab provides Kirchhoff’s Voltage Law (KVL) and Current Law (KCL) verification—enter voltage or current values at nodes and check whether the sum balances to zero. Includes an SVG circuit diagram that updates with your calculated values.

• 12 formulas across voltage (V=IR, V=P/I, V=√(PR)), current, resistance, and power
• Calculate All button derives both missing values from any two known inputs
• Interactive SVG circuit diagram with live V, I, R, P labels
• Kirchhoff’s Voltage Law: sum voltages around a loop and verify balance
• Kirchhoff’s Current Law: sum currents at a node and verify balance
• Copy step-by-step calculation results to clipboard

Frequently Asked Questions

Which two values do I need to solve the circuit?

Any two of voltage (V), current (I), resistance (R), or power (P). The remaining two are always derivable. For example, knowing V and R gives you I = V/R and P = V²/R.

Can I use this for AC circuits?

Only for resistive (purely ohmic) AC loads. For circuits with capacitors or inductors, you need impedance calculations that account for phase angles and reactance. This tool assumes DC or purely resistive AC, which is correct for heaters, incandescent bulbs, and resistor networks.