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Electric Field Calculator

Find the radial electric field produced by an isolated point charge. Positive indicates outward from a positive charge; negative indicates inward toward a negative charge.

Enter every field, including explicit zeros when permitted. Decimal and scientific notation are accepted; commas, fractions and blanks are rejected. Each input must be finite and no larger than 1 billion in absolute value. Observe the stated units and domain limits.

Signed radial field (N/C)71900.41434
Field magnitude (N/C)71900.41434

How to use this calculator

  1. Enter every quantity in the unit printed beside its field.
  2. Select Calculate or press Enter.
  3. Read the labeled results and compare them with the assumptions below.

Formula and method

E = kQ/r² for a point charge in vacuum.

The calculation runs locally in your browser. If any entry is invalid or a mathematical condition is undefined, the prior result is hidden so it cannot be mistaken for a new answer.

Worked example

Using Source charge (µC) = 2, Distance from charge (m) = 0.5, the formula returns Signed radial field (N/C) = 71900.41434, Field magnitude (N/C) = 71900.41434. The displayed default result is generated from these same inputs.

Limitations and safety

Models one point charge in vacuum. It does not sum multiple vector fields or account for conductors, dielectric materials and finite charge distributions. Avoid contact with electrical hazards. Results use floating-point arithmetic and are displayed to about 10 significant digits; measurement uncertainty usually supports fewer. Verify units before relying on a result.

Frequently asked questions

Is electric field the same as force?

No. Field is force per unit positive test charge, measured in newtons per coulomb.

Why might a measured result differ?

The formula isolates the stated model. Real systems can add uncertainty, losses, changing properties, geometry or forces that are not among the inputs.

How should I handle units?

Convert every value to the unit shown beside its field before calculating. A numerically valid value in the wrong unit will still produce a wrong result.

Review notes and reference

Reviewed October 3, 2026. The default example and an independent edge or scaling case were checked against expected values. The live script was also checked for blank, text, comma-formatted, non-finite and out-of-range entries. Method reference. Constants use the values stated in the formula. This page’s explanation and example are original.

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