Ohms Law Calculator

Ohm's Law calculator: enter any two values of voltage, current, and resistance to compute the third with step-by-step solution.

Voltage (V)

Current (I)

Resistance (R)

Result

Please check your inputs.

📖 How to Use This Tool

Enter any two known values into the calculator fields — Voltage (V), Current (I), or Resistance (R). Leave the third field blank.

Select the correct units for each value (e.g., volts, amps, ohms). The tool supports common metric units.

Click the 'Calculate' button. The tool will instantly compute the missing value using Ohm’s Law.

Review the step-by-step solution that shows how the result was derived, including the formula rearrangement.

Use the 'Reset' button to clear all fields and start a new calculation.

📝 What Is Ohms Law Calculator?

Ohm’s Law is a fundamental principle in electrical engineering and physics that defines the relationship between voltage, current, and resistance in a circuit. Named after Georg Ohm, it states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance. The Ohm’s Law Calculator is an interactive online tool that lets you quickly compute any one of these three values when you know the other two. This tool matters because it saves time and reduces errors in circuit analysis, whether you're a student learning electronics, a hobbyist building a project, or a professional troubleshooting a system. Instead of manually rearranging Ohm’s Law equations, you simply input your known values and get instant, accurate results with a clear step-by-step breakdown. It’s an essential resource for anyone working with electrical circuits.

🧮 Formula

V = I × R

Where: - V = Voltage (in volts) - I = Current (in amperes) - R = Resistance (in ohms) The tool uses this formula to compute the missing value. For example, if you enter current and resistance, it multiplies them to find voltage. If you enter voltage and current, it divides voltage by current to find resistance. If you enter voltage and resistance, it divides voltage by resistance to find current. Each calculation is shown step by step.

💡 Tips for Best Results

✨💡 Always double-check your units — using milliamps instead of amps can skew results by a factor of 1000.

✨📐 Use the step-by-step solution to understand how the formula rearranges — great for studying.

✨🔄 Try different combinations: entering the same two values but swapping which is unknown can verify your work.

✨⚡ Remember Ohm’s Law only applies to purely resistive circuits; for components like inductors or capacitors, AC impedance is different.

❓ Frequently Asked Questions

What is Ohm’s Law?

Ohm’s Law states that the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance. It is expressed as V = I × R.

Can I use this calculator for AC circuits?

Ohm’s Law applies to DC circuits and to AC circuits with purely resistive loads. For AC circuits with reactive components (capacitors, inductors), you need to consider impedance, which is a more complex relationship.

What units does the calculator support?

The Ohm’s Law Calculator supports common metric units such as volts, millivolts, kilovolts for voltage; amps, milliamps, microamps for current; and ohms, kiloohms, megohms for resistance. Simply select the appropriate unit from the dropdown menu.