Joules to Calories Converter

How to convert joules to calories

calories = joules ÷ 4.184

The joule is the SI unit of energy. 1 thermochemical calorie is exactly 4.184 joules. 1 International Table calorie is exactly 4.1868 joules.

Dividing by 4.184 is exact. Written as a multiplication the factor is a repeating decimal, 1 J = 0.2390057361377… cal, so a rounded multiplier such as 0.239 is slightly off. This converter keeps the exact fraction (125/523) and rounds only the result it shows.

Worked example: 100 J

1. Start with the value in joules: 100 J.
2. Divide by 4.184, because 1 calorie = 4.184 joules: 100 ÷ 4.184 = 23.90057361….
3. Round to the precision you need: 23.90 cal to two decimals.

Joules and calories side by side

Joules to calories chart

Print chart

Joules from 1 to 100 converted to calories with the exact factor, shown to five significant digits.

Joules to calories, part 1 of 4

J	cal
1	0.23901
2	0.47801
3	0.71702
4	0.95602
5	1.195
6	1.434
7	1.673
8	1.912
9	2.1511
10	2.3901
11	2.6291
12	2.8681
13	3.1071
14	3.3461
15	3.5851
16	3.8241
17	4.0631
18	4.3021
19	4.5411
20	4.7801
21	5.0191
22	5.2581
23	5.4971
24	5.7361
25	5.9751

Joules to calories, part 2 of 4

J	cal
26	6.2141
27	6.4532
28	6.6922
29	6.9312
30	7.1702
31	7.4092
32	7.6482
33	7.8872
34	8.1262
35	8.3652
36	8.6042
37	8.8432
38	9.0822
39	9.3212
40	9.5602
41	9.7992
42	10.038
43	10.277
44	10.516
45	10.755
46	10.994
47	11.233
48	11.472
49	11.711
50	11.95

Joules to calories, part 3 of 4

J	cal
51	12.189
52	12.428
53	12.667
54	12.906
55	13.145
56	13.384
57	13.623
58	13.862
59	14.101
60	14.34
61	14.579
62	14.818
63	15.057
64	15.296
65	15.535
66	15.774
67	16.013
68	16.252
69	16.491
70	16.73
71	16.969
72	17.208
73	17.447
74	17.686
75	17.925

Joules to calories, part 4 of 4

J	cal
76	18.164
77	18.403
78	18.642
79	18.881
80	19.12
81	19.359
82	19.598
83	19.837
84	20.076
85	20.315
86	20.554
87	20.793
88	21.033
89	21.272
90	21.511
91	21.75
92	21.989
93	22.228
94	22.467
95	22.706
96	22.945
97	23.184
98	23.423
99	23.662
100	23.901

calories = joules ÷ 4.184. Factors: NIST SP 811, BIPM SI Brochure. unitcheck.net/energy/joules-to-calories/

Small calories, not food Calories

This page converts to the small calorie (cal). The Calorie on a food label is the kilocalorie: 1 kcal = 1,000 cal = 4,184 J. So 100 J is 23.90 cal but only 0.0239 kcal. Two definitions of the calorie are in use, the thermochemical calorie (exactly 4.184 J, the default here) and the International Table calorie (exactly 4.1868 J). They differ by 0.07%.