3 Electric Field Calculators, Compared

E = kQ/r² is not a difficult equation. It is, however, an equation where the charge arrives in nanocoulombs, the distance in centimetres, and Coulomb’s constant is 8.99 × 10⁹ — so the arithmetic is three unit conversions wrapped around one division, and that is where the marks get lost.

Finding a calculator for it is oddly hit-and-miss. Search results are dominated by pages that compute the field but not the force, or the force but not the field, or that quietly assume SI units without saying so — which is fine until you paste in a value in microcoulombs and get an answer three orders of magnitude out with no warning that anything went wrong.

How to judge an electric field calculator

Does it handle prefixed units? Charges are almost never given in whole coulombs. A calculator that only accepts base SI has left you the error-prone part.

Does it distinguish field from force? E is field strength in newtons per coulomb; F is the force on a test charge. Related, not interchangeable.

Does it show the formula? For coursework, seeing the substitution is worth more than seeing the result.

Can it handle more than one charge? Superposition of several charges is a different and much longer calculation.

The comparison

Facts checked August 2026; plans can change.

Calculator Online: Electric Field

This is the most flexible of the three. You can choose a single point charge or a system of charges, and pick whether to solve for the field, the distance, or the charge — which matters because textbook problems frequently give you the field and ask for the separation, and most calculators only run the equation forwards.

The flexibility costs a few clicks. If your question is genuinely “one charge, one distance, what is E”, you are selecting options before you reach it.

Calculator Academy: Electric Field

Calculator Academy gives you the number quickly with the formula displayed alongside, which is the right combination for checking your own working. You can see whether the tool substituted what you thought it substituted.

It does less to help with unit prefixes, which is where most real errors in this calculation actually occur.

BYJU’S Electric Field Calculator

BYJU’S is aimed at students, and the surrounding material reflects that — the calculation comes with explanation, which is genuinely useful if you are meeting Coulomb’s law for the first time rather than checking an answer.

It sits inside a commercial education platform, so expect prompts toward courses and accounts around the tool itself.

Electric Field Strength Calculator

Ours does the single-charge case directly. Enter a point charge and a distance and it returns the electric field strength at that point using the standard Coulomb’s law field formula. One equation, one screen, in your browser, with no account.

Two limitations worth stating. It handles a single point charge, so problems involving two or more charges — where you must add field vectors, not magnitudes — need Calculator Online’s system mode or manual superposition. And it computes field strength rather than force on a test charge, so if the question asks for F you have one more multiplication to do yourself.

Which one to pick

• If you need to solve for distance or charge rather than field, use Calculator Online.
• If you want the formula shown next to the result for checking, use Calculator Academy.
• If you are learning the concept rather than checking an answer, use BYJU’S.
• If you have one charge and one distance and want E immediately, use ours.

How to do it with Electric Field Strength Calculator

1. Open the Electric Field Strength Calculator.
2. Enter the point charge and the distance from it, converting prefixes to base units first.
3. Read the field strength in newtons per coulomb, and sanity-check the exponent — halving the distance should quadruple the field. More physics tools are in the tools directory.

You might also need

• Scientific Notation Converter — for the exponents this calculation generates.
• Ohm’s Law Calculator — for the circuit half of the same coursework.

Frequently asked questions

Is there a free electric field calculator that doesn’t need an account?

Yes — all three linked calculators are free to use online. Ours needs no account because the site has no signup at all.

What is the difference between electric field and electric force?

The field E is a property of space created by a charge, measured in newtons per coulomb. The force F is what a second charge experiences in that field, given by F = qE. The field exists whether or not anything is there to feel it.

Does the field have a direction?

Yes — it is a vector, pointing away from a positive charge and toward a negative one. Calculators return the magnitude, so with multiple charges you must add the vectors rather than the numbers. NIST’s reference on constants and units is the authority for the value of Coulomb’s constant used in these calculations.

Final thought

Convert the units before you touch the calculator. Nearly every wrong answer in this calculation is a prefix, not a formula.

Try the free Electric Field Strength Calculator