Electric field calculator (point charge)
The electric field and potential around a point charge: E = k·q / (εᵣ·r²) and V = k·q / (εᵣ·r). Enter the charge, the distance and the surrounding medium — the dielectric weakens the field, water by about 80× — and see the values with SI prefixes plus a field-line diagram.
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All Energy & power tools →Open Electric field calculator (point charge) and you get an answer straight away, with no account to create. It covers E = k·q / (εᵣ·r²) and V = k·q / (εᵣ·r). Enter the charge, the distance and the surrounding medium — the dielectric weakens the field, water by about 80× — and see the values with SI prefixes plus a field-line diagram — adjust any of them and the result follows immediately.
How to use it
- Open the tool — no signup or install needed.
- Enter your input or adjust the available options.
- Get your result instantly, then copy or download it.
Frequently asked questions
What does Electric field calculator (point charge) do?
The electric field and potential around a point charge: E = k·q / (εᵣ·r²) and V = k·q / (εᵣ·r). Enter the charge, the distance and the surrounding medium — the dielectric weakens the field, water by about 80× — and see the values with SI prefixes plus a field-line diagram.
What does a concrete case look like?
q = 1 nC, r = 1 cm → E ≈ 9,0 × 10⁴ V/m — the tool shows every step in between, not just the final figure.
What does it take into account?
It factors in E = k·q / (εᵣ·r²) and V = k·q / (εᵣ·r). Enter the charge, the distance and the surrounding medium — the dielectric weakens the field, water by about 80× — and see the values with SI prefixes plus a field-line diagram. Change any of them and the output follows immediately.
When would I actually use this?
Putting a number on a bill: what an appliance costs to run, whether a solar array covers the load, and how much heating a room actually needs.
What is the most common mistake?
Confusing power with energy. A kilowatt is a rate and a kilowatt-hour is a quantity; a 2 kW heater on for half an hour uses 1 kWh, and only the second figure appears on a bill.
How is Electric field calculator (point charge) different from Magnetic field of a current calculator?
They sit next to each other but answer different questions: Magnetic field of a current calculator is the one to open when you need it to the magnetic flux density B produced by a current, for three classic geometries: a long straight wire (B = μ₀I/2πr), the centre of a single circular loop (B = μ₀I/2R) and inside a long solenoid (B = μ₀nI). Choose the geometry and enter the current; only that mode's fields matter. Pick whichever matches what you're starting from — both are free.
Is there a tool for the next step?
Boiling point calculator (altitude & pressure) is the closest one after this: Find the boiling point of water at any altitude or atmospheric pressure. Water boils below 100 °C as you climb because the air pushes down less — this tool converts altitude to pressure with the barometric formula, then to a boiling point via the Clausius-Clapeyron relation. Vital for high-altitude cooking and canning.
What else is worth having open alongside it?
Boiling point elevation calculator and Freezing point depression calculator — they come up in the same task often enough to be worth a second tab.
Where do the figures come from?
The arithmetic is exact for the rating and the tariff you enter. Nameplate wattage is a maximum, not an average, and solar output depends on latitude, orientation and shading that no formula can guess.