Energy Converter

Enter an amount of energy, choose its unit and the unit you want.

Updated October 27, 2026

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<iframe src="/embed/en/unit-converters/energy-converter/" width="480" height="640" title="Energy Converter" loading="lazy" style="border:0;max-width:100%"></iframe>
<script>window.addEventListener('message',function(event){if(event.origin!==''||!event.data||event.data.type!=='calc-embed-height')return;var f=document.getElementsByTagName('iframe');for(var i=0;i<f.length;i++){if(f[i].contentWindow===event.source){f[i].style.height=event.data.height+'px';}}});</script>

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Formula

result = value × (joules in the from unit) ÷ (joules in the to unit)

Every unit is stored as a fixed multiple of the base unit (J), so any pair converts in one step.

Worked example

1 kWh to BTU: 1 kWh = 3,600,000 J and 1 BTU (IT) = 1,055.05585262 J, so 3,600,000 ÷ 1,055.05585262 = 3412.141633 BTU.

Quick reference

1 kWh = 3.6 MJ, 1 kcal = 4.184 kJ, 1 Wh = 3600 J, 1 BTU = 1055.056 J.

Frequently asked questions

How many kJ is 1 kcal?

1 kilocalorie is exactly 4.184 kJ. A 500 kcal meal is therefore 500 × 4.184 = 2,092 kJ.

How many BTU is 1 kWh?

1 kWh is 3,412.14 BTU (IT), from 3,600,000 J ÷ 1,055.05585 J per BTU.

What is the difference between a calorie and a food Calorie?

Food labels use the kilocalorie (kcal), often written Calorie. It equals 1,000 small calories, or 4,184 joules.

How many joules are in a kilowatt-hour?

Exactly 3,600,000 J, because 1 kW for 3,600 seconds is 1,000 W × 3,600 s.

How we calculate

Energy Converter

Formula

Worked example

Quick reference

Frequently asked questions

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