# Joules to Volts Calculator

URL: https://speedycalculator.com/calculators/conversion/joules-to-volts/
Last updated: 2026-10-25

> The joules to volts calculator finds the voltage (potential difference) from the energy transferred and the electric charge moved, using V = E ÷ Q, and works backwards to energy or charge.

## Inputs

- Energy (J, kJ, Wh, eV)
- Charge (C, mC, mAh, Ah)

## Results

- Voltage

## Formula

```
V = E ÷ Q   (1 V = 1 J/C)
```

## Explanation

A volt is one joule of energy per coulomb of charge. A 9 V battery gives 9 joules to every coulomb that flows through the circuit. The electronvolt (eV) is the energy one electron gains crossing one volt.

### How to use the Joules to Volts Calculator

- **Energy**
- **Charge**
- Every result field is editable: type into **Voltage** and **Energy** plus every other field update to match.

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Energy is divided by charge. Type a voltage into the result to find the energy needed.

### Inputs explained

FieldWhat to enterEnergyUnits: J, kJ, Wh, eVChargeUnits: C, mC, mAh, Ah

### Example values

How the main result changes when **Energy** changes and everything else stays at the example values above:

Energy (J)Voltage (V)4.54.56.756.759911.2511.2513.513.51818

## Worked example

Inputs — Energy: 9 J; Charge: 1 C.

Results — **Voltage = 9 V**.

## FAQ

**How many volts is 1 joule per coulomb?**
1 V.

**How much energy is in a 3,000 mAh, 3.7 V battery?**
3.7 × 10,800 C ≈ 40 kJ (11.1 Wh).

**What formula does the Joules to Volts Calculator use?**
V = E ÷ Q   (1 V = 1 J/C).


## Sources

- [BIPM – The International System of Units (SI Brochure, 9th edition)](https://www.bipm.org/en/publications/si-brochure)