What is the formula for joules to volts?

Voltage (V) equals energy (E in joules) divided by charge (Q in coulombs): V = E / Q. This comes directly from the definition of electric potential.

What is one volt in terms of joules and coulombs?

One volt is defined as one joule per coulomb (1 V = 1 J/C). It represents the work done per unit charge to move charge between two points.

Can I convert joules to volts without knowing the charge?

No. Voltage depends on both energy and charge. Without the charge value in coulombs, the conversion cannot be completed.

Can I use E / Q for a charged capacitor?

Not directly for the final terminal voltage. A capacitor charged from zero stores E = ½QV, so its final voltage is V = 2E/Q when E and Q are its final stored energy and charge. The E/Q formula represents energy transferred per unit charge across a constant potential difference.

Does this work for AC circuits?

This formula applies to DC or instantaneous values. For AC circuits, use RMS values of energy and charge, or apply additional conversion steps.

Joules to Volts Calculator

Enter energy in joules and charge in coulombs to instantly calculate the equivalent voltage in volts using V = E / Q.

Input Values

Enter energy and charge to calculate voltage.

Energy (E)

Charge (Q)

Formula: V = E ÷ Q — Voltage (V) = Energy (J) / Charge (C)

Result

Calculated voltage in volts.

Enter values and click Calculate.

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Summary

Enter energy in joules and charge in coulombs to instantly calculate the equivalent voltage in volts using V = E / Q.

How it works

Enter the energy value in joules (J) in the first field.
Enter the electric charge value in coulombs (C) in the second field.
The calculator applies the formula V = E / Q instantly.
The result in volts (V) is displayed along with the input summary.
Adjust either value and click Calculate again to update the result.

Use cases

Calculate a constant potential difference from transferred energy and charge.
Verify battery voltage from energy capacity and charge measurements.
Solve physics homework problems involving Ohm's law and electrostatics.
Design circuits that require precise voltage from a stored energy budget.
Convert between electrical units in laboratory experiments.
Cross-check datasheet values for energy storage components.

Frequently Asked Questions

Last updated: 2026-09-19 · Reviewed by Nham Vu