Electrical heat
Joule Heating Calculator
Electrical resistance converts electrical energy into thermal energy. Choose the quantities you know and calculate the power dissipated as heat and the energy released over time.
Calculate resistive heating
Why current matters so strongly
At fixed resistance, heating follows I²R. Doubling current therefore multiplies resistive power by four. This is why conductor size, contact quality and current limits matter in electrical systems.
Power generation and temperature are different questions
A resistor dissipating 20 W does not have one universal operating temperature. Temperature depends on its thermal resistance to the surroundings, mounting, surface area, airflow and nearby materials.
Electrical heaters use the same effect deliberately
Kettles, toasters and resistive heaters are designed to generate substantial Joule heat in an element and then transfer that energy to water, air or food.
Related reading
Read the electrical heating guide, estimate electronic junction temperature, or explore a thermal-resistance path.