Creators
Md Jony Islam Author
Md Jony Islam
CalculatorToolsProjectExpert
Reviewers
Małgorzata Koperska, MD Steven Wooding
Last updated: November 14, 2025

Ohm’s Law Calculator | Voltage, Current, Resistance, Power

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Ohm's Law Calculator

Ohms Law Calculator

Quickly calculate voltage, current, resistance, or power using Ohm’s Law. Enter any two values to compute the others instantly with this online calculator.

electrical engineering calculator

An Ohm Law Calculator is a tool that enables users to calculate voltage, current, resistance, or power in electrical circuits in a fast and precise manner. The calculator can be used to find the remaining parameters using a combination of standard Ohm and power equations by just entering two known values, so it proves to be invaluable in learning, troubleshooting, and circuit design.

voltage current resistance calculator

The Ohm Law Calculator is a web-based calculator that is used to make computations in electricity easier. Users are able to compute other quantities immediately once they have entered any two known values of the voltage (V), current (I), resistance (R), or power (P). It is ideal among students, electricians, engineers, and hobbyists who are involved with electrical circuits. This is because this calculator saves time, minimizes manual errors in calculations, and assists in the design and analysis of circuits efficiently. It has a friendly interface, is responsive, and does not need installation.

Work, Installation, Input to Output

Work:

  • Uses formulas:
  • V=I × R
  • I= V/R
  • R=V/I
  • P=V × I
  • Calculates unknown values based on the given inputs.

Installation: No installation required; works in any modern web browser.

Input:

  • Any two of: Voltage (V), Current (I), Resistance (R), Power (P)

Output:

  • Remaining unknowns calculated automatically

Testing and Final Adjustments

Test calculator with standard and extreme electrical values (e.g., small currents, high voltages). Make sure that any formula is accurate. Make sure that you are not allowed to enter impossible inputs (e., negative resistance). Mobile and desktop check responsiveness. Make sure that when you put in two known numbers, the remaining two are also calculated correctly. Make provision of clear error messages due to missing or invalid inputs. Make sure the calculator is able to work with decimals and round off correctly. Streamline UI to ensure that all the input fields and calculated outputs are well indicated. Provide dynamism in the case of instant updates. Assure the user-friendliness of students and professionals.

Frequently Asked Questions - Ohms Law Calculator:

What is an Ohm’s Law Calculator?

A tool to calculate voltage, current, resistance, or power using Ohm’s Law formulas.

How do I use it?

Enter any two known values among V, I, R, or P, and the calculator computes the rest.

What is Ohm’s Law?

A fundamental law stating V = I × R, relating voltage, current, and resistance.

Can it calculate power?

Yes, it can calculate electrical power using P = V × I.

Is it free?

Yes, the Ohm’s Law Calculator is completely free online.

Can I use it on mobile devices?

Yes, it is fully responsive and works on all devices.

Who can use this calculator?

Students, electricians, engineers, and anyone working with electrical circuits.

Can it handle decimal values?

Yes, it accepts and calculates values with decimals accurately.

What if I input invalid values?

The calculator will show an error message for missing or impossible inputs.

Why is Ohm’s Law important?

It is essential for analyzing and designing electrical circuits accurately.

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Md Jony Islam

Md Jony Islam

Calculator Tools Project

Founder of Earthbondhon.com

a free online tools website designed to make everyday and engineering-related calculations easier for students, professionals, and hobbyists. The site offers a wide range of basic calculators across key categories, including Electrical Calculators, Electronic Calculators, and Time & Date Calculators.