Current Calculator – Calculate Electrical Current (Amps)

Calculate the current flowing through any circuit. Enter voltage and resistance to apply Ohm's Law and find current in amperes with our electrical current calculator.

Calculation Mode

Voltage (V)

Resistance (Ω)

How the Current Calculator Works

Select Calculation Mode

Choose between Ohm's Law (I = V/R), Power formula (I = P/V), or Impedance method (I = V/Z).

Enter Circuit Values

Input voltage and resistance, power, or impedance values based on your selected calculation mode.

Get Current Result

Receive instant current calculation in amperes with automatic unit conversion for mA or µA.

Features of This Electrical Current Calculator

Multiple Calculation Methods

Calculate current using Ohm's Law, power formula, or impedance for AC circuits.

Auto Unit Conversion

Results automatically display in A, mA, or µA based on magnitude for easy reading.

Formula Display

See the exact formula used for each calculation to understand and verify results.

AC and DC Support

Calculate current for both DC circuits (resistance) and AC circuits (impedance).

Free Electrical Tool

Completely free current calculator for students, electricians, and engineers.

Mobile-Friendly Design

Calculate current on any device, anywhere - perfect for field work and labs.

Current Calculation Formulas

Method	Formula	When to Use
Ohm's Law	I = V / R	DC circuits with known resistance
Power Formula	I = P / V	When power consumption is known
Impedance Method	I = V / Z	AC circuits with impedance

Frequently Asked Questions

How do I calculate current in a circuit?

Current is calculated using Ohm's Law: I = V / R, where I is current in amperes, V is voltage in volts, and R is resistance in ohms. For example, 12V across 100Ω gives 0.12A or 120mA of current.

What is the difference between AC and DC current?

DC (Direct Current) flows in one direction constantly, while AC (Alternating Current) reverses direction periodically. DC is used in batteries and electronics, while AC powers homes and businesses through the electrical grid.

How do I calculate current from power and voltage?

Use the formula I = P / V, where P is power in watts and V is voltage. For example, a 60W bulb at 120V draws 0.5A of current (60 ÷ 120 = 0.5).

What is impedance in AC circuits?

Impedance (Z) is the total opposition to AC current flow, combining resistance and reactance. It's measured in ohms like resistance but accounts for frequency-dependent effects in capacitors and inductors.

How do I convert between A, mA, and µA?

1 Ampere (A) = 1,000 milliamperes (mA) = 1,000,000 microamperes (µA). To convert A to mA, multiply by 1,000. To convert mA to µA, multiply by 1,000.

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