Voltage Calculator

Enter 2 values to get the other values and press the Calculate button:

An image illustrating the step-by-step process of using a Voltage Calculator. The image shows a user entering the power and current values into the calculator's input fields. The next step displays the calculator automatically calculating the voltage based on the entered values. This image visually guides the user on how to use the Voltage Calculator, a helpful tool for calculating electrical voltage.

A voltage calculator is a handy tool that helps you determine important electrical properties. By inputting voltage parameters, you can predict the current, resistance, or power in a circuit.

Why Voltage Matters

✔️ Powering electrical devices

✔️ Preventing component damage

✔️ Mitigating shock/fire risks

✔️ Conserving energy

✔️ Transmitting signals effectively

What is Voltage?

Voltage represents electromotive force or “electrical pressure” applied to push current through resistive materials. Measured in volts (V), higher voltage enables more electrons to flow against friction like water pressure forcing flow through narrow pipes. Lower voltage currents struggle against resistance.

Using the Voltage Calculator

Relating voltage to other electric properties involves:

  1. Inputting any two known values
  2. Selecting appropriate units
  3. Computing remaining metrics

For example, a 3-ohm resistor with 0.5 amp current reflects a 1.5-volt potential difference. Simple!

Sample Calculations





10 Ω

2 A

20 V

40 W

5 Ω

0.25 A

1.25 V

0.31 W

Useful relating loads, wiring ratings, and batteries.

Digital Multimeter Usage

Handy electrical multimeters instantly measure values for input into the calculator. They detect:

  • Voltage - Volt scale
  • Current - Amp scale via probes
  • Resistance - Ohm scale

This enables real-world troubleshooting by cross-checking circuit parameters against ratings.

6 Ways Electrical Voltage is Measured

  1. Multimeter

  • A digital or analog multimeter directly measures the voltage between two probed points in a circuit. Select the appropriate voltage scale (V, mV, kV) based on the expected readings.
  1. Clamp Meter

  • Clamp-style ammeters conveniently measure the current flowing through a wire, which can then be used with known resistance to calculate voltage using Ohm's Law (V = I x R).
  1. Voltmeter

  • Either stand-alone units or integrated on other test equipment. Voltmeters connect across components to take readings without needing to break circuits.
  1. Oscilloscope

  • Plots a graph of voltage over time on-screen. Allow visualizing and quantifying AC voltages or transient spikes.
  1. Data Loggers

  • Capture networked, time-based voltage readings for remote monitoring of critical systems. Store measurement trends.
  1. Load Cells

  • Specialized voltage sensors convert parameters like pressure, force or strain into proportional electrical signals for instrumentation systems.

Ohm's Law Applications

The electrical correlations powering the calculator originate from Ohm's famous discovery stating:

Voltage (V) = Current (I) x Resistance (R)

This core relationship mathematically interlinks the primary circuit properties as explored further here.

Calculations Using Ohm's Law

Permuting the Equation enables solving for any single unknown:

  • V = I x R ==> Voltage
  • I = V / R ==> Current
  • R = V / I ==> Resistance

Substitute reference chart:

Electrical Property





volts (V)



amps (A)



ohms (Ω)

So once securing any two metrics, the third extrapolates through rearrangement.

Scenarios Applying Ohm's Law

Everyday use cases include:

  • Sizing wires and fuses
  • Selecting appropriate batteries
  • Troubleshooting shorted windings
  • Computing parallel resistances
  • Designing timing circuits

This indispensable relation touches practically all electrical engineering disciplines and daily needs for safe power transfer.


Note Ohm's strict assumptions:

❌ Time invariant voltages/currents

❌ Homogenous conductive materials
❌ Temperature stable

Real-world non-linear effects require advanced modeling.

Frequently Asked Questions (FAQs)

Q1: What is voltage?

Voltage is the force or potential difference between two points in an electrical circuit, measured in volts (V). It determines the intensity of the electric current flowing through the circuit.

Q2: How is voltage measured?

Voltage is measured using a device called a voltmeter. The voltmeter is connected to the two points between which the voltage is to be measured, and it displays the voltage reading in volts.

Q3: What is the significance of voltage in electrical circuits?

Voltage is essential in electrical circuits as it determines the flow of electric current. 


In summary, an adjustable voltage calculator empowers both electricians and aspiring inventors alike by effortlessly relating key variables for verification, safety, and optimal electrical system function. 

Read More: Voltage and Current | Basic Concepts Of Electricity

                     How To Use Online Free Voltage Calculator?