Energy conversion

online energy unit conversion calculator

Instant conversions! Your math assistant for calculating energy conversions online quickly and simply.

Energy Converter



From joules (J) to calories (cal)

0.000

1 J = 0.239006 cal


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The following multimedia calculator is a tool to convert energy units to another delivery value, for example, joules, kilojoules, watt-hours, kilowatt-hours, etc.

How does the energy unit calculator work?

The online energy conversion calculator allows you to enter a value and select the destination unit. It will automatically provide the converted value based on the equivalence between both units.

  1. Selection of the source unit:
    • The dropdown menu allows you to select the energy measure of input (for example, joules, kilocalories, BTU, watt-hours, etc.).
  2. Entering the value to convert:
    • Enter the numerical value you want to convert.
  3. Selection of the destination unit:
    • Select the energy unit to which you want to convert the value.
  4. Automatic conversion
    • The calculator converts energy automatically and accurately.

The online tool has no limits on the number of conversions that can be made, so you can use it whenever you want.

Examples of calculation for energy conversions:

  • To convert 500 joules to kilocalories, simply multiply 500 J by the equivalence of 1 J to calories and then divide by 1,000 to get kilocalories: 500 J×0.239 cal/J=119.5 cal500 J×0.239 cal/J=119.5 cal and 119.5 cal÷1,000=0.1195 kcal119.5 cal÷1,000=0.1195 kcal.
  • If we want to transform energy units to go from 150 kilowatt-hours to megajoules, the calculation would be 150 kWh×3,600,000 J/kWh=540,000,000 J150 kWh×3,600,000 J/kWh=540,000,000 J and then divide by 1,000,000 to get megajoules: 540,000,000 J÷1,000,000=540 MJ540,000,000 J÷1,000,000=540 MJ.
  • To convert 2,000 British Thermal Units (BTU) to kilojoules, you just have to do the calculation: 2,000 BTU×1,055.06 J/BTU=2,110,120 J2,000 BTU×1,055.06 J/BTU=2,110,120 J and then divide by 1,000 to get kilojoules: 2,110,120 J÷1,000=2,110.12 kJ2,110,120 J÷1,000=2,110.12 kJ.
  • If we want to convert 3 megaelectronvolts to joules, the conversion would be 3 MeV×1.60218×10−13 J/MeV=4.80654×10−13 J3 MeV×1.60218×10−13 J/MeV=4.80654×10−13 J.

🟧 Note: Remember that you can perform complex calculations with our online scientific calculator. It’s a great tool!

What energy units can I convert in this calculator?

In this online energy converter you can convert the following values:

  • Joules (J)
  • Kilojoules (kJ)
  • Megajoules (MJ)
  • Gigajoules (GJ)
  • Calories (cal)
  • Kilocalories (kcal)
  • Watt-hours (Wh)
  • Kilowatt-hours (kWh)
  • Megawatt-hours (MWh)
  • Gigawatt-hours (GWh)
  • British Thermal Unit (BTU)
  • Electronvolts (eV)
  • Megaelectronvolts (MeV)
  • Ergs (erg)
  • Therms (therm)
  • Foot-pound force (ft⋅lbf)
  • Ton of refrigeration (TR)

Energy unit conversion table

We provide the following energy unit equivalence table to quickly consult the possible conversions between different energy measures:

Energy equivalences
Energy unit Joules (J) Calories (cal) Kilowatt-hours (kWh) British Thermal Units (BTU)
Joule (J) 1 J 0.239 cal 2.78 × 10^-7 kWh 0.000947817 BTU
Kilojoule (kJ) 1,000 J 239 cal 0.000278 kWh 0.947817 BTU
Megajoule (MJ) 1,000,000 J 239,006 cal 0.278 kWh 947.817 BTU
Gigajoule (GJ) 1,000,000,000 J 239,006,000 cal 278 kWh 947,817 BTU
Calorie (cal) 4.184 J 1 cal 1.163 × 10^-6 kWh 0.00396567 BTU
Kilocalorie (kcal) 4,184 J 1,000 cal 0.001163 kWh 3.96567 BTU
Watt-hour (Wh) 3,600 J 860.421 cal 0.001 kWh 3.41214 BTU
Kilowatt-hour (kWh) 3,600,000 J 860,421 cal 1 kWh 3,412.14 BTU
Megawatt-hour (MWh) 3,600,000,000 J 860,421,000 cal 1,000 kWh 3,412,140 BTU
Gigawatt-hour (GWh) 3,600,000,000,000 J 860,421,000,000 cal 1,000,000 kWh 3,412,140,000 BTU
British Thermal Unit (BTU) 1,055.06 J 252.164 cal 0.000293071 kWh 1 BTU
Electronvolt (eV) 1.60218 × 10^-19 J 3.827 × 10^-20 cal 4.4505 × 10^-26 kWh 1.51857 × 10^-22 BTU
Megaelectronvolt (MeV) 1.60218 × 10^-13 J 3.827 × 10^-14 cal 4.4505 × 10^-20 kWh 1.51857 × 10^-16 BTU
Erg (erg) 1 × 10^-7 J 2.39 × 10^-8 cal 2.77778 × 10^-11 kWh 9.47817 × 10^-8 BTU
Therm (therm) 105.5 × 10^6 J 25.210 × 10^6 cal 29.3071 kWh 100,000 BTU
Foot-pound force (ft⋅lbf) 1.35582 J 0.324048 cal 3.76616 × 10^-7 kWh 0.00128507 BTU
Ton of refrigeration (TR) 3.51685 × 10^6 J 840,455 cal 0.9765625 kWh 3,412 BTU

🟧 If you have any other questions about transforming energy measures, you can contact us from the contact section in the footer.

Frequently asked questions about converting energy units – FAQ

  • How to convert kilowatt-hours (kWh) to joules (J)?

To convert kWh to joules, you must multiply the number of kWh by 3.6 × 10^6. Example, 1 kWh = 3.6 × 10^6 J.

  • How to convert joules (J) to kilowatt-hours (kWh)?

To convert joules to kWh, divide the number of joules by 3.6 × 10^6. For example, the calculations would be: 3.6 × 10^6 J = 1 kWh.

  • How are watts (W) converted to kilowatts (kW)?

You have to divide the number of watts by 1000. For example, 1000 W = 1 kW.

  • How to convert kilowatts (kW) to watts (W)?

Multiply the number of kilowatts by 1000. An example, 1 kW = 1000 W.

  • How do you convert calories (cal) to joules (J)?

The equivalence is: 1 calorie = 4.184 joules. So, to convert, multiply the number of calories by 4.184.

  • How to convert joules (J) to calories (cal)?

Divide the number of joules by 4.184, given that the equivalence is: 4.184 J = 1 cal.

  • What is a BTU and how is it converted to joules?

A BTU (British Thermal Unit) is a unit of energy used primarily in the United States for heating and cooling. It is equivalent to 1055 joules. To convert BTU to joules, multiply the number of BTU by 1055.

  • How to convert BTU to kilowatt-hours?

First, convert BTU to joules (1 BTU = 1055 J), and then convert those joules to kWh by dividing by 3.6 × 10^6. So you have the following calculation: 1 BTU ≈ 0.000293 kWh.

  • How to convert megajoules (MJ) to kilowatt-hours (kWh)?

Knowing that 1 MJ is equal to 0.27778 kWh. Divide the number of megajoules by 3.6 to get kWh.

  • How to convert kilowatt-hours to megajoules?

You will have to multiply the number of kWh by 3.6 to get MJ. For example, 1 kWh = 3.6 MJ.

  • How are watt-hours (Wh) converted to joules?

To go from Wh to joules. Multiply the number of Wh by 3600 given that 1 Wh = 3600 J.

  • How to convert joules to watt-hours?

You will have to divide the number of joules by 3600. For example, 3600 J = 1 Wh.