Accurate Ohm's Law Calculator | Voltage, Current, Resistance & Power | Free Online Tool

Ohm's Law Calculator is an online tool that calculates the relationship between electric current, voltage, and resistance, based on Ohm's Law. It is a useful tool for electricians, engineers, and students who want to calculate the value of any of the three variables and solve problems related to electrical circuits.

Using the Ohm's Law Calculator is very easy. There are three input fields where you can enter the values of the two variables you know, and the calculator will automatically calculate the third variable. The three variables are:

  1. Voltage (V): The electrical potential difference between two points in a circuit, measured in volts (V).
  2. Current (I): The flow of electric charge through a conductor, measured in amperes (A).
  3. Resistance (R): The property of a material that opposes the flow of electric current, measured in ohms (Ω).

To use the Ohm's Law Calculator, follow these simple steps:

  1. Choose the variable you want to calculate (voltage, current, or resistance).
  2. Enter the values of the two known variables in the input fields.
  3. Click on the "Calculate" button, and the calculator will display the result in the third input field.

The main advantage of using the Ohm's Law Calculator is its speed and accuracy. Instead of manually calculating the value of the unknown variable using Ohm's Law formula (V = IR, I = V/R, or R = V/I), you can get an instant result with just a few clicks. This saves time and reduces the chance of making calculation errors. Additionally, the calculator is user-friendly and provides a clear interface for easy navigation.

Moreover, the Ohm's Law Calculator also includes a graphical representation of the circuit and its values, making it easier to understand the relationship between the variables. The calculator also allows you to switch between different units of measurement, such as volts, millivolts, kilovolts, amperes, milliamperes, kiloamperes, ohms, kiloohms, and megohms, which makes it more versatile and convenient to use for a wide range of applications.

In conclusion, the Ohm's Law Calculator is a useful tool for anyone who deals with electrical circuits and needs to calculate the values of voltage, current, and resistance quickly and accurately. Its user-friendly interface, graphical representation, and the ability to switch between different units of measurement make it an essential tool for electricians, engineers, and students.


It is believed that these calculations are accurate, but not guaranteed. Use at your own risk!