Coulomb's Law Calculator

Category: Physics
- January 10, 2026
| |

Coulomb's Law describes the electrostatic force between two charged particles. This fundamental principle of electrostatics states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

This calculator allows you to determine the electrostatic force, electric field, and potential energy between charged particles using Coulomb's Law.

What would you like to calculate?

C
? The magnitude of the first charge in Coulombs (C). For example, an electron has a charge of -1.602 × 10⁻¹⁹ C.
C
? The magnitude of the second charge in Coulombs (C).
? The distance between the centres of the two charges.

Display Options

? Include the effect of a dielectric medium between the charges. This will reduce the electrostatic force by a factor of the dielectric constant.

About Coulomb's Law

Coulomb's Law, formulated by French physicist Charles-Augustin de Coulomb in 1785, describes the electrostatic force between two electrically charged particles. It is a fundamental principle in electrostatics.

The Mathematical Expression:

Coulomb's Law is mathematically expressed as:

F = k × (|q₁ × q₂|) / r²

Where:

  • F is the electrostatic force between the charges (in Newtons, N)
  • k is Coulomb's constant (8.9875 × 10⁹ N·m²/C²)
  • q₁ and q₂ are the magnitudes of the charges (in Coulombs, C)
  • r is the distance between the centres of the charges (in metres, m)
Related Electric Field Equations:

The electric field at a distance r from a point charge q is given by:

E = k × |q| / r²

The electric potential at a distance r from a point charge q is given by:

V = k × q / r

The electric potential energy of two point charges q₁ and q₂ separated by a distance r is given by:

U = k × q₁ × q₂ / r
Effect of Dielectric Media:

When charges are in a medium other than vacuum, the electrostatic force is reduced by a factor equal to the dielectric constant (ε) of the medium:

F = k × (|q₁ × q₂|) / (ε × r²)

The dielectric constant is a measure of the medium's ability to "store" electric field energy. The higher the dielectric constant, the more the medium weakens the electric field.

Medium Dielectric Constant (ε)
Vacuum 1.0 (exact)
Air (at STP) 1.00059
Water 80
Glass 5-10
Plastic 2-4
Paper 3.7
Oil 2.4
Key Applications:
  • Atomic and Molecular Structure: Coulomb's Law explains the attractive force between electrons and the nucleus in atoms.
  • Electrical Engineering: Used in designing capacitors, insulators, and other electrical components.
  • Chemical Bonding: Ionic bonds and electrostatic interactions in molecules are described by Coulomb's Law.
  • Electrostatic Precipitators: Used to remove particles from a gas stream by applying an electric charge.
  • Lightning: The buildup and discharge of electric charge in clouds can be explained using Coulomb's Law.
  • Biological Processes: Many biological processes involve electrostatic interactions between charged molecules.

Understanding Coulomb's Law

Coulomb's Law is a key principle in Physics that explains how charged particles interact with each Other. Developed by Charles-Augustin de Coulomb in the 18th century, it states that the force between two charges is directly related to the size of the charges and inversely related to the distance between them. This means that the closer two charges are, the stronger the force between them. The law is fundamental in fields like electrostatics and helps us understand forces in everyday life.

Coulomb's Law Calculator Overview

This Coulomb's Law Calculator is designed to help you calculate the electrostatic force, electric field, and potential energy between two charged particles. Whether you're a student working on assignments or someone with a curiosity about electric forces, this tool makes it easy to perform complex calculations. With just a few inputs, you can obtain meaningful results that enhance your understanding of electrostatics.

What Can You Calculate?

  • Electrostatic Force between two charges
  • Electric Field generated by a point charge
  • Electric Potential at a given distance from a charge
  • Potential Energy of two charges

The calculator provides options to choose the specific calculation you want to perform. You can easily switch between calculating electrostatic force, electric field, potential energy, and electric potential, depending on your needs.

Input Fields and Options

When using the calculator, you'll need to enter several values. For electrostatic force, you’ll input the magnitudes of the two charges and the distance between them. Similar inputs are required for other calculations, such as electric field strength and potential energy. There are also preset values for common charge types like electrons and protons, which save time and make calculations simpler.

Advanced Features for Detailed Calculations

This calculator isn’t just basic; it offers advanced features for those who want to dive deeper into their calculations. You can adjust the number of decimal places for the results and choose between standard and scientific notation formats. Additionally, there's an option to consider the effect of dielectric materials, which can impact the electrostatic force between charges. This is particularly useful for more complex scenarios in physics and engineering.

Understanding Your Results

Once you've entered your values and performed the calculation, the results will show the electrostatic force, direction, and other relevant data. The tool also displays Coulomb's constant for reference. If you’ve opted for dielectric considerations, the results will show how the medium affects the electrostatic force. This information helps you see the practical implications of your calculations in real-world scenarios.

Applications of Coulomb's Law

  • Understanding atomic structure and chemical bonds
  • Designing electrical components like capacitors
  • Explaining phenomena like lightning and electrostatic precipitators
  • Studying interactions in biological systems

Coulomb’s Law has numerous applications in various fields. From explaining the basic structure of atoms to the functioning of electrical devices, understanding this law is essential for students and professionals alike. This calculator aids in visualising these concepts and applying them in practical situations.

Get Started with the Coulomb's Law Calculator

With all these features and insights, the Coulomb’s Law Calculator is an invaluable tool for anyone looking to explore the world of electrostatics. It’s user-friendly and tailored to provide accurate results quickly, making it ideal for learners and enthusiasts alike. Dive in and start exploring the forces that shape our universe!