Convert joules to volts given charge in coulombs. Supports 4 modes: J+C→V, V+C→J, J+A+s, and Wh→J with comprehensive reference tables.
The joules to volts calculator converts between energy (joules) and voltage (volts) using the fundamental relationship V = J ÷ C, where C is charge in coulombs. Voltage is energy per unit charge — you cannot convert joules to volts without knowing the charge.
This calculator provides four modes: joules + coulombs → volts, volts + coulombs → joules, joules + amps + seconds (to derive coulombs), and watt-hours → joules. Each mode shows all equivalent energy units including watt-hours, kWh, calories, BTU, and megajoules.
The reference table shows voltage for common joule-coulomb combinations, and a key-relationships section summarizes all relevant electrical formulas. It is helpful for classroom problem-solving, battery calculations, and quick checks during circuit design reviews. It also reduces unit-mismatch mistakes when moving between textbook equations, lab measurements, and practical electronics calculations in mixed-unit workflows and time-pressured troubleshooting tasks in real projects. This keeps results consistent across teams.
Physics students and electrical engineers need to relate energy (joules) to voltage and charge. This calculator handles the three-variable relationship and provides all energy equivalents in one view so calculations stay consistent across homework, lab notes, design documents, and cross-team technical discussions during implementation, review, and troubleshooting. It also helps validate assumptions quickly.
Volts = Joules ÷ Coulombs. V = J / C. Coulombs = Amps × Seconds. 1 watt-hour = 3,600 joules.
Result: 100 J ÷ 5 C = 20 V
100 joules of energy distributed over 5 coulombs of charge yields 20 volts. This is the same as V = J / C = 100 / 5 = 20.
Voltage (volts) is NOT energy. It is energy per unit charge — a ratio. A 12V battery and a 12V power supply both provide 12 joules per coulomb, but the power supply might deliver millions of coulombs (massive energy) while a small battery delivers only a few.
A typical AA battery (1.5V, 2,500 mAh) stores: 1.5V × 2.5Ah × 3,600 = 13,500 joules. A Tesla Model 3 battery (400V nominal, 75 kWh) stores: 75 × 3,600,000 = 270,000,000 joules. Both are energy stored as electrical potential.
The joule, volt, coulomb, watt, and amp are all interconnected: J = V × C = W × s. V = J / C = W / A. C = A × s. W = V × A = J / s. Understanding these relationships is the foundation of electrical engineering.
Not directly. Volts = Joules ÷ Coulombs. You need to know the charge (in coulombs) to compute voltage.
V = J / C. Voltage equals energy divided by charge. Equivalently, J = V × C (energy equals voltage times charge).
1 volt means 1 joule per coulomb. If 1 coulomb of charge moves through 1 volt, 1 joule of energy is transferred.
1 amp = 1 coulomb per second. So 10 amps for 5 seconds = 50 coulombs.
An electron-volt (eV) is the energy gained by a single electron moving through 1 volt of potential. 1 eV = 1.602 × 10⁻¹⁹ joules.
Multiply watt-hours by 3,600. Example: 100 Wh × 3,600 = 360,000 J.