Mendeleev
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Energy

Common, useful unit conversions for science and everyday measurement.

J → kJ› J → Wh› J → kWh› J → cal› J → kcal› kJ → J› kJ → Wh› kJ → kWh› kJ → cal› kJ → kcal› Wh → J› Wh → kJ› Wh → kWh› Wh → cal› Wh → kcal› kWh → J› kWh → kJ› kWh → Wh› kWh → cal› kWh → kcal› cal → J› cal → kJ› cal → Wh› cal → kWh› cal → kcal› kcal → J› kcal → kJ› kcal → Wh› kcal → kWh› kcal → cal›
Mendeleev · Guide

Understand it before converting

Energy is not just a classroom quantity: it appears constantly in electricity, food, heating, mechanics and physics. Units are chosen for practical reasons. Some are convenient in everyday life, while others dominate scientific or technical work. This page deliberately focuses on familiar units — joules, kilojoules, watt-hours, kilowatt-hours, calories and kilocalories — instead of presenting a long catalogue of rarely used formats. Every pair links to a dedicated conversion page with the calculation rule, worked examples and useful reference values. The aim is to get the answer quickly while still understanding what is being converted and whether the result makes physical sense.

The key idea

Binding energy is the energy required to separate a nucleus into its constituent nucleons. It is related to the nucleus’s mass defect through E = Δmc².

Why it matters

Binding energy per nucleon helps explain why both fusion of light nuclei and fission of very heavy nuclei can release energy.