How It Works

The calculator uses Ohm's Law to determine current from voltage and resistance. Divide the voltage across the circuit by its resistance to find the current flowing through it.

I = V ÷ R, where I is current in amperes (A), V is voltage in volts (V), and R is resistance in ohms (Ω).

Example

For example, if a circuit has 12 V across a resistance of 4 Ω, the current is 3 A because I = 12 ÷ 4 = 3 A.

Frequently Asked Questions

What is the formula for electrical current?

Using Ohm's Law, current is calculated with I = V ÷ R, where V is voltage in volts and R is resistance in ohms.

How do you calculate current from voltage and resistance?

Divide the voltage by the resistance. For example, 12 V ÷ 4 Ω = 3 A.

What unit is electrical current measured in?

Electrical current is measured in amperes, commonly called amps (A).

What is Ohm's Law?

Ohm's Law describes the relationship between voltage, current, and resistance in an electrical circuit. The relationship can be written as V = IR.

What is the current if the voltage is 12 V and resistance is 4 Ω?

The current is 3 A. Using I = V ÷ R, the calculation is 12 ÷ 4 = 3 A.

Can I calculate current if I know voltage and resistance?

Yes. When voltage and resistance are known, divide voltage by resistance to calculate current using Ohm's Law.