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Kilocalories to Joules Converter

Convert kilocalories (food Calories) (kcal) to joules (watt-seconds) (J), with the formula, a conversion table and exact factors.

Change the values and press Calculate to work out your own figures.

Enter an amount of energy, choose its unit and the unit you want. The answer is exact until it is shown, and the same value appears in every other unit.

A number, fraction (3/8), mixed number (1 1/2), scientific notation (2.5e6) or a simple sum such as 2*3.
The unit you want the answer in. Swap exchanges the two units.
Result
4,184 J
kilojoules
4.184 kJ
megajoules
0.004184 MJ
gigajoules
4.184 × 10⁻⁶ GJ
calories (thermochemical)
1,000 cal
megacalories
0.001 Mcal
watt-hours
1.16222222222 Wh
kilowatt-hours
0.00116222222222 kWh
megawatt-hours
1.16222222222 × 10⁻⁶ MWh
British thermal units (IT)
3.96566683139 Btu
million Btu
3.96566683139 × 10⁻⁶ MMBtu
therms (100,000 Btu)
3.96566683139 × 10⁻⁵ thm
quads (10¹⁵ Btu)
3.96566683139 × 10⁻¹⁵ quad
electronvolts
2.61144739675 × 10²² eV
kiloelectronvolts
2.61144739675 × 10¹⁹ keV
megaelectronvolts
2.61144739675 × 10¹⁶ MeV

1 kcal = 4,184 J

Show the working
  1. 1 kcal = 4184 J
  2. 1 × 4184 = 4184 J

How to convert kilocalories to joules

1 kcal = 4,184 J, so multiply by 4,184 to go from kilocalories (food Calories) to joules (watt-seconds). Going the other way, 1 J = 0.000239005736138 kcal.

J = kcal × 4,184
kcal = J × 0.000239005736138

Worked example:

1 kcal = 4184 J
5 × 4184 = 20920 J

Kilocalories to joules table

KilocaloriesJoules
1 kcal4,184 J
2 kcal8,368 J
3 kcal12,552 J
4 kcal16,736 J
5 kcal20,920 J
6 kcal25,104 J
7 kcal29,288 J
8 kcal33,472 J
9 kcal37,656 J
10 kcal41,840 J
15 kcal62,760 J
20 kcal83,680 J
25 kcal104,600 J
30 kcal125,520 J
40 kcal167,360 J
50 kcal209,200 J
75 kcal313,800 J
100 kcal418,400 J
250 kcal1,046,000 J
500 kcal2,092,000 J
1000 kcal4,184,000 J

About the units

Kilocalories (kcal)
Kilocalories (food Calories), a specialised unit. Definition: NIST SP 811 Appendix B.8, factors for units listed alphabetically.
Joules (J)
Joules (watt-seconds), a metric unit. Definition: BIPM SI Brochure, 9th edition (SI units, prefixes and units accepted for use with the SI).

Formula version 0.1.0Reviewed