Ohm's Law Calculator

Calculate Voltage, Current, Resistance, and Power from any two known values.

Known Values

Voltage (V)

Enter the known voltage (v).

Current (I)

Enter the known current (i).

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All Results

⚡ Voltage

—V

〰️ Current

—A

🔧 Resistance

—Ω

💡 Power

—W

Formula Reference

Voltage (V)

V = I × R

V = P / I

V = √(P × R)

Current (I)

I = V / R

I = P / V

I = √(P / R)

Resistance (R)

R = V / I

R = V² / P

R = P / I²

Power (P)

P = V × I

P = I² × R

P = V² / R

Documentation

How It Works

Ohm's Law is the foundation of electrical engineering. It relates Voltage (V), Current (I), and Resistance (R) in a linear circuit. Combined with the power equation, any two known electrical quantities can determine the other two.

Select any two known values from the dropdown, enter their amounts, and this calculator will compute all four quantities instantly.

Core Formulas

Last Updated: February 28, 2026

Disclaimer: For educational and reference purposes only. Always consult a qualified electrician for real-world electrical work.

Frequently Asked Questions