What formula is used?

The calculator uses E(J) = I(A) × V(V) × t(s). This follows from the definition of power P = I × V (watts) and energy E = P × t (joules). It assumes a constant DC load.

A joule (J) is the SI unit of energy. One joule equals one watt of power applied for one second (1 J = 1 W · s = 1 V · A · s).

How does this relate to coulombs?

Charge Q (coulombs) = I × t. Energy E = Q × V. So E = I × V × t. The intermediate step through coulombs confirms the formula.

Can I use this for AC circuits?

The formula gives correct real-energy results for DC and for AC when you enter the RMS current and RMS voltage together with a unity power factor. For AC with a non-unity power factor, the real energy is E = I(RMS) × V(RMS) × PF × t. This tool assumes PF = 1 (DC or purely resistive AC).

How do I convert joules to kilowatt-hours?

1 kWh = 3,600,000 J. Divide joules by 3,600,000 to get kilowatt-hours. The result panel shows this conversion automatically.

What if I know watts instead of amps and volts?

If you already know the power in watts, simply multiply by time in seconds: E(J) = P(W) × t(s). You can derive current as I = P / V if needed.

Amps to Joules Calculator

Calculate energy in joules from current (A), voltage (V), and time (s) using E = I × V × t.

Input Parameters

Current (A)

Voltage (V)

Time (s)

Result

Enter values and press Calculate

Formula Reference

Energy

E (J) = I (A) × V (V) × t (s)

Charge

Q (C) = I (A) × t (s)

Power Relation

E (J) = P (W) × t (s)

Result copied!

Summary

This calculator converts electric current in amperes (A) to energy in joules (J) by combining current, voltage, and time. The formula E = I × V × t relates the charge delivered (coulombs = A × s) to the potential difference (volts) to give total energy in joules. It is useful for sizing batteries, calculating heat dissipation, and estimating energy consumption over a given period.

How it works

Enter the current in amperes (A).
Enter the voltage in volts (V).
Enter the time in seconds (s).
The calculator applies E = I × V × t and displays the result in joules (J).
Additional conversions (kJ, Wh, kWh) are shown for convenience.
Use the Reset button to start a new calculation.

Use cases

Calculate the energy stored in or delivered by a battery during discharge.
Estimate heat generated by a resistive element over a set duration.
Size capacitor banks based on required joule output.
Verify energy consumption of appliances over a timed interval.
Determine weld energy in resistance welding systems.
Calculate energy delivered by a defibrillator pulse.
Design motor drive systems based on acceleration energy.
Estimate energy use of LED lighting rigs during production runs.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu