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
| Field | What to enter |
|---|---|
| Energy | Units: J, kJ, Wh, eV |
| Charge | Units: 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) |
|---|---|
| 4.5 | 4.5 |
| 6.75 | 6.75 |
| 9 | 9 |
| 11.25 | 11.25 |
| 13.5 | 13.5 |
| 18 | 18 |
Formula
V = E ÷ Q (1 V = 1 J/C)Worked example
Inputs — Energy: 9 J; Charge: 1 C.
Results — Voltage = 9 V.
Frequently asked questions
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).