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Current Calculator

Calculate electrical current from voltage and resistance using Ohm’s law, plus power.

Current
2 A
I = 12 V ÷ 6 Ω = 2 A (Ohm’s law)
Power
24 W
Voltage
12 V
Resistance
6 Ω

Results are for ideal resistive DC circuits. Real-world components may vary — verify against component datasheets and consult a qualified electrician for mains or safety-critical applications.

How it works

  1. 1Enter the supply voltage in volts (V) and the load resistance in ohms (Ω).
  2. 2The calculator applies I = V ÷ R to find the current in amperes.
  3. 3Power is shown via P = V × I, giving both quantities at once.

Use cases

  • Sizing wires and fuses by checking the current a resistive load draws.
  • Verifying LED or motor-driver circuits before powering up.
  • Demonstrating Ohm’s law for physics or electronics coursework.

Frequently asked questions

What is the formula for current?

Current I = V ÷ R (Ohm’s law). For example, 12 V across 6 Ω gives 2 A. When power is known, I = P ÷ V.

Why does it show — when resistance is zero?

Dividing by zero is undefined and represents a short circuit with theoretically infinite current, so the calculator shows — for that input.

How is power found from current and voltage?

Power P = V × I. With 12 V and 2 A the power is 24 W. Equivalently, P = I² × R or P = V² ÷ R.

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