Voltage Calculator (Ohm's Law)
Calculate voltage from current and resistance.
A
Ω
Result
12 V
Voltage: 12 V
Result in all units
Step-by-step solution
V = I × R
What Is Ohm's Law?
Ohm's law describes the relationship between voltage, current, and resistance in a circuit. It is the fundamental law of electronics, and when two are known the third can be found.
How is it calculated?
How Is It Calculated?
V = I × R
From this, I = V ÷ R and R = V ÷ I.
- Enter the two known values.
- The third is found automatically.
For example, 12 V and 4 Ω: I = 12 ÷ 4 = 3 A.
Frequently Asked Questions
What are the units of voltage, current, and resistance?
Voltage is measured in volts (V), current in amperes (A), and resistance in ohms (Ω).