Ohm's Law: 12V Battery with 4Ω Resistance
A 12 V source connected to a 4 Ω resistor draws a current of 3 A.
How to use this tool
- Enter voltage (v), current (i) and resistance (r) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your voltage and the full breakdown beneath it.
Calculate the current drawn by a 4 Ω load connected to a 12 V car battery using Ohm's Law.
Frequently asked questions
- What units are used?
- Volts (V) for voltage, Amperes (A) for current, Ohms (Ω) for resistance, and Watts (W) for power. Keep units consistent.
- Does Ohm's Law apply to AC circuits?
- For pure resistors, yes. For capacitors and inductors you need impedance Z (complex resistance), and V = IZ replaces V = IR.