Ohms Law Calculator
Solve DC circuit relationships across Voltage (V), Current (I), Resistance (R), and Electrical Power (P).
About Ohm's Law
Ohm's Law states that current through a conductor between two points is directly proportional to voltage across those points and inversely proportional to resistance.
Formulas
- Voltage: V = I × R
- Current: I = V / R
- Resistance: R = V / I
- Electric Power: P = V × I = I² × R = V² / R
Worked Example
With 12 Volts and 2 Amperes flowing through a circuit:
- Resistance: R = 12 / 2 = 6 Ohms (Ω)
- Power Dissipated: P = 12 × 2 = 24 Watts (W)
Frequently Asked Questions
Does Ohm's Law apply to AC circuits?
In AC circuits with capacitors or inductors, resistance is replaced by impedance (Z), which accounts for phase shifts.
What is an ohmic vs non-ohmic conductor?
Ohmic conductors maintain constant resistance across varying voltages; non-ohmic components (like diodes and transistors) have voltage-dependent resistance.
How does wire heating affect resistance?
Most conductive metals have a positive temperature coefficient: resistance increases as operating temperature rises.
What is electrical power measured in?
Power is measured in Watts (W), indicating the rate of electrical energy consumption (1 Watt = 1 Joule/second).
Calculate in three steps
- 1Enter your valuesUse the fields above and check the units shown beside each input.
- 2Run the calculationSelect Calculate to refresh the result with your latest values.
- 3Review or shareCompare the result, reset the form, print it, or share this page.