# Joule Heating Calculator

URL: https://speedycalculator.com/calculators/physics/joule-heating/
Last updated: 2026-10-30

> The Joule heating calculator finds the heat produced by an electric current flowing through a resistance over a period of time.

## Inputs

- Current I (A, mA, µA, kA)
- Resistance R (Ω, kΩ, MΩ, mΩ)
- Time t (s, ms, min, h, days)

## Results

- Heat produced Q
- Power

## Formula

```
Q = I²·R·t
```

## Explanation

Current through a resistor produces heat – useful in kettles, toasters and fuses, wasteful in cables and chips. Doubling the current quadruples the heat.

### How to use the Joule Heating Calculator

- **Current I**
- **Resistance R**
- **Time t**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Enter the current, resistance and time.

### Inputs explained

FieldWhat to enterCurrent IUnits: A, mA, µA, kAResistance RUnits: Ω, kΩ, MΩ, mΩTime tUnits: s, ms, min, h, days

### What each result means

- **Heat produced Q** = [Current I]^2×[Resistance R]×[Time t]
- **Power** = [Current I]^2×[Resistance R]

### Example values

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

Current I (A)Heat produced Q (J)2.53,7503.758,437.5515,0006.2523,437.57.533,7501060,000

## Worked example

Inputs — Current I: 5 A; Resistance R: 10 Ω; Time t: 60 s.

Results — **Heat produced Q = 15,000 J**; Power = 250 W.

## Key terms

- **Joule heating**: Heat from current through resistance.

## FAQ

**Why does heat depend on I²?**
Power = I²R – current enters twice.

**Why are transmission lines high voltage?**
Lower current means much less Joule heating loss.

**What is Joule heating used for?**
Heaters, fuses, incandescent lamps, soldering irons.

**Is it the same as ohmic heating?**
Yes.


## Sources

- [OpenStax – University Physics Volume 2](https://openstax.org/details/books/university-physics-volume-2)
- [HyperPhysics (Georgia State University)](http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html)