Electric Field Calculator for E, Force and Potential

The electric field calculator helps you work with three closely related electrostatics quantities: electric field strength, electrostatic force, and electric potential. All three come from Coulomb's law and describe how electric charges influence the space around them. In the point-charge model, the interaction depends on the charge magnitude, the sign of the charge, and the separation distance. This calculator uses the Coulomb constant k = 8.9875517923 × 10^9 N·m²/C², which is the standard value used in introductory and engineering physics. When you choose Electric field mode, the calculator applies E = kQ / r². Electric field strength tells you how strongly a point charge would push or pull another positive test charge placed at distance r. The result is shown in newtons per coulomb, which is also equivalent to volts per meter. A positive source charge produces a field pointing outward, while a negative charge produces a field pointing inward, so the sign of the result can be useful when you want directional context rather than magnitude alone. Force mode uses F = kQ1Q2 / r². This gives the electrostatic force between two point charges. If the charges have the same sign, the force is positive in this simplified one-dimensional treatment and represents repulsion. If the charges have opposite signs, the result becomes negative and represents attraction. Because the formula contains r² in the denominator, even a small change in separation can produce a very large change in force, which is one reason electrostatic interactions become so important at small scales. Potential mode uses V = kQ / r. Electric potential describes the potential energy per unit charge created by a point charge at a location. It is especially useful in circuit theory, electrostatics problems, and energy-based reasoning. Unlike the electric field expression, potential depends on 1 / r rather than 1 / r², so it falls off more slowly with distance. That makes it a convenient quantity for comparing positions around a charged particle or conductor. This calculator is best used for idealized point-charge problems in vacuum or air, where the Coulomb constant is a good approximation. In real materials, permittivity changes the interaction, and extended charge distributions may require integration or numerical methods rather than a single closed-form equation. Even so, the formulas here are the standard starting point for homework, lab checks, and quick engineering estimates.