Calories to Joules

Convert cal to J instantly — with a table, common energy values, and a live calculator.

1 cal equals 4.18 J.

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Result (J)4.18 J

cal to J table

calJ
1 cal4.18 J
2 cal8.37 J
3 cal12.55 J
5 cal20.92 J
10 cal41.84 J
15 cal62.76 J
20 cal83.68 J
25 cal104.6 J
30 cal125.52 J
40 cal167.36 J
50 cal209.2 J
60 cal251.04 J
75 cal313.8 J
90 cal376.56 J
100 cal418.4 J
120 cal502.08 J
150 cal627.6 J
200 cal836.8 J
250 cal1046 J
300 cal1255.2 J
400 cal1673.6 J
500 cal2092 J

J to cal (reverse)

Jcal
1 J0.239 cal
2 J0.478 cal
3 J0.717 cal
5 J1.2 cal
10 J2.39 cal
15 J3.59 cal
20 J4.78 cal
25 J5.98 cal
30 J7.17 cal
40 J9.56 cal
50 J11.95 cal
60 J14.34 cal
75 J17.93 cal
90 J21.51 cal
100 J23.9 cal
120 J28.68 cal
150 J35.85 cal
200 J47.8 cal
250 J59.75 cal
300 J71.7 cal
400 J95.6 cal
500 J119.5 cal

Common energy values

calJ
5 cal20.92 J
10 cal41.84 J
25 cal104.6 J
50 cal209.2 J
75 cal313.8 J
100 cal418.4 J
120 cal502.08 J
150 cal627.6 J
200 cal836.8 J
300 cal1255.2 J
400 cal1673.6 J
500 cal2092 J

How it scales

1052093144180255075100cal

1 kWh in other units

860kcal3.6MJ3412BTU1000Wh

The ratio at a glance

1 cal4.18 J

Joules, kWh, and calories — the key energy units

Joules (J), kilojoules (kJ), and megajoules (MJ) are the SI units of energy. The kilowatt-hour (kWh) is the unit on your electricity bill and equals 3.6 MJ. With calories there are two sizes that must not be confused: the kilocalorie (kcal) on nutrition labels equals exactly 4184 J (4.184 kJ), while the small calorie (cal) is only 4.184 J — they differ by a factor of 1000. The BTU (British thermal unit) equals 1055.06 J and is used in heating and air-conditioning.

Energy conversions are exact and rest on fixed factors — for more unit pairs, use our energy conversion hub.

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Frequently asked questions

How many J are in 1 cal?

1 cal equals 4.18 J.

How many J are in 2 cal?

2 cal equal 8.37 J.

How do I convert cal to J?

Multiply the energy in cal by 4.18 to get J.

What is a (small) calorie (cal)?

The small calorie (cal) equals exactly 4.184 joules (thermochemical calorie). 1000 of them make one kilocalorie (kcal) — the “Calorie” on nutrition labels.

What are these energy units used for?

Joules (J), kilojoules (kJ), and megajoules (MJ) are the SI units of energy. The kilowatt-hour (kWh) is the unit on your electricity bill, kilocalories (kcal) appear on food labels, and the BTU (British thermal unit) is used in heating and air-conditioning.

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