Energy Converter
Convert joules, calories, kilowatt-hours, and BTU.
Energy units, converted
Energy shows up in joules for physics, calories for food, kilowatt-hours on your electricity bill, and BTU in heating specs. One kilowatt-hour is 3.6 million joules, which puts an appliance's draw in perspective.
It bridges everyday and technical worlds — comparing the kilowatt-hours on your power bill to the joules in a physics problem, or the BTU rating of an air conditioner to watts.
Food vs science calories
A dietary Calorie is actually a kilocalorie, a common factor-of-1000 trap this avoids. All math runs locally in your browser. Your figures never leave the browser.
Frequently Asked Questions
How does the energy converter work?
Energy is normalized to joules. One kilowatt-hour is 3.6 million joules, which is about 3,412.14 BTU.
When should I use this converter?
Use it for electricity bills, nutrition comparisons, heating systems, battery estimates, and physics homework checks.
What is the main limitation?
Food Calories are kilocalories; the lowercase calorie is much smaller, so choose the unit carefully.
Is this converter private?
Yes. The conversion runs entirely in your browser, so your values are not uploaded, stored, or sent to a server.
More free browser utilities for conversion, formatting, and technical cleanup.