Calorie to Watt Hour Converter

A calorie (cal), also called a small calorie or gram calorie, is a unit of energy equal to approximately 4.184 joules. It represents the energy needed to raise the temperature of one gram of water by one degree Celsius at standard atmospheric pressure.

The calorie was defined by French chemist Nicolas Clément in 1824 as a unit for measuring heat. It was widely used in chemistry and physics for calorimetry and thermodynamics before being largely replaced by the joule in scientific applications, though it remains in use for food energy.

Calories are primarily used in chemistry for small-scale energy measurements, in some scientific literature, and occasionally in food and nutrition contexts. However, they've been largely replaced by joules in scientific applications and by kilocalories (food calories) in nutrition.

A watt-hour (Wh) is a unit of energy equal to the energy consumed by a device with a power rating of one watt operating for one hour. It equals 3,600 joules and is commonly used for measuring energy in small electronic devices.

The watt-hour developed alongside electrical technology as a convenient way to measure energy consumption in smaller electrical devices. It became particularly important with the rise of portable electronics and battery-powered devices where kilowatt-hours would be impractically large.

Watt-hours are commonly used for measuring battery capacity in portable electronics, energy consumption of small appliances, and in renewable energy systems for small-scale applications. They're standard for smartphone batteries, laptop batteries, and small solar power systems.