Ans

Unit converter

Joules to thermochemical calories.

Convert J to cal and cal to J. Type in either box and the other follows. These are small calories of 4.184 J, the physics unit — not the food calories on a packet, which are a thousand times larger.

J → calExact definition
—
Joules to calories — common values, to 6 significant figures.
Jcal
1 J0.239006 cal
10 J2.39006 cal
50 J11.9503 cal
100 J23.9006 cal
500 J119.503 cal
1000 J239.006 cal
5000 J1195.03 cal
10000 J2390.06 cal
1 J=0.2390057361 cal 1 cal=4.184 J

Definitions

  • The joule is the SI unit of energy: one newton acting through one metre.
  • The thermochemical calorie is exactly 4.184 J — the small calorie, roughly the energy to warm 1 g of water by 1 °C.
  • This conversion is exact by definition. 1 J = 0.2390057361 cal.
  • The food calorie is the kilocalorie: 1 kcal = 1000 cal. Nutrition labels marked "calories" mean kcal.

How it works

One direction multiplies and the other divides by the same number, so nothing is lost by going back and forth.

The value passes through J, the unit every other energy unit on the site is defined against, rather than a number written into this page on its own. That is why the figure here, the figure in the table above and the general energy converter always agree.

Display precision limits significant figures rather than decimal places, because one fixed number of decimals is useless across a range this wide. Very large and very small results switch to scientific notation with a proper superscript exponent. The editable box always holds a plain number at full working precision, so you can carry on from either side.

Common questions this answers: how many calories in a joule (0.239006), how many joules in a calorie (thermochemical) (4.184), and what 1000 J is in calories (239.006 cal).

From the maker of Ans — a scientific calculator you can own. Same idea: a proper instrument, nothing in the way.