How many joules are in 1 calorie?

1 cal equals 4.184 J. This is an exact conversion factor defined by NIST.

How do I convert calories to joules?

Multiply the value in cal by the conversion factor. For example, 10 cal = 41.84 J. Use our calculator above for instant results.

Is the calories to joules conversion exact?

Yes, this conversion is mathematically exact based on the international definition of these units (NIST SP 811).

Can I convert calories to joules offline?

Yes! OmniConvert runs entirely in your browser — no internet connection needed after the page loads. Your data never leaves your device, ensuring complete privacy.

What is the difference between calories and joules?

Calories (cal) and Joules (J) are both units of energy but belong to different measurement systems. 1 cal = 4.184 J. Use the converter above to switch between them instantly.

Calories to Joules (cal → J) — Free Online Converter

cal → J Reference Table

cal	J
0.001 cal	0.004184 J
0.002 cal	0.008368 J
0.003 cal	0.012552 J
0.004 cal	0.016736 J
0.005 cal	0.02092 J
0.006 cal	0.025104 J
0.007 cal	0.029288 J
0.008 cal	0.033472 J
0.009 cal	0.037656 J
0.01 cal	0.04184 J
0.02 cal	0.08368 J
0.03 cal	0.12552 J
0.04 cal	0.16736 J
0.05 cal	0.2092 J
0.06 cal	0.25104 J
0.07 cal	0.29288 J
0.08 cal	0.33472 J
0.09 cal	0.37656 J
0.1 cal	0.4184 J
0.2 cal	0.8368 J
0.3 cal	1.2552 J
0.4 cal	1.6736 J
0.5 cal	2.092 J
0.6 cal	2.5104 J
0.7 cal	2.9288 J
0.8 cal	3.3472 J
0.9 cal	3.7656 J
1 cal	4.184 J
1.5 cal	6.276 J
2 cal	8.368 J
2.5 cal	10.46 J
3 cal	12.552 J
3.5 cal	14.644 J
4 cal	16.736 J
4.5 cal	18.828 J
5 cal	20.92 J
5.5 cal	23.012 J
6 cal	25.104 J
6.5 cal	27.196 J
7 cal	29.288 J
7.5 cal	31.38 J
8 cal	33.472 J
8.5 cal	35.564 J
9 cal	37.656 J
9.5 cal	39.748 J
10 cal	41.84 J
11 cal	46.024 J
12 cal	50.208 J
13 cal	54.392 J
14 cal	58.576 J
15 cal	62.76 J
16 cal	66.944 J
17 cal	71.128 J
18 cal	75.312 J
19 cal	79.496 J
20 cal	83.68 J
25 cal	104.6 J
30 cal	125.52 J
35 cal	146.44 J
40 cal	167.36 J
45 cal	188.28 J
50 cal	209.2 J
55 cal	230.12 J
60 cal	251.04 J
65 cal	271.96 J
70 cal	292.88 J
75 cal	313.8 J
80 cal	334.72 J
85 cal	355.64 J
90 cal	376.56 J
95 cal	397.48 J
100 cal	418.4 J
120 cal	502.08 J
125 cal	523 J
130 cal	543.92 J
140 cal	585.76 J
150 cal	627.6 J
160 cal	669.44 J
175 cal	732.2 J
180 cal	753.12 J
200 cal	836.8 J
225 cal	941.4 J
250 cal	1046 J
275 cal	1150.6 J
300 cal	1255.2 J
350 cal	1464.4 J
400 cal	1673.6 J
450 cal	1882.8 J
500 cal	2092 J
600 cal	2510.4 J
700 cal	2928.8 J
750 cal	3138 J
800 cal	3347.2 J
900 cal	3765.6 J
1000 cal	4184 J
1200 cal	5020.8 J
1250 cal	5230 J
1500 cal	6276 J
1750 cal	7322 J
2000 cal	8368 J
2500 cal	10460 J
3000 cal	12552 J
4000 cal	16736 J
4500 cal	18828 J
5000 cal	20920 J
6000 cal	25104 J
7000 cal	29288 J
7500 cal	31380 J
8000 cal	33472 J
9000 cal	37656 J
10000 cal	41840 J
15000 cal	62760 J
20000 cal	83680 J
25000 cal	104600 J
50000 cal	209200 J
75000 cal	313800 J
100000 cal	418400 J

Values based on NIST SP 811 conversion factors

Why Convert Calories to Joules?

Converting between calories (cal) and joules (J) is one of the most common energy conversions. Whether for engineering, cooking, travel, or science, knowing how to quickly convert cal to J saves time and prevents errors.

Energy conversions from cal to J are crucial for dietitians, physicists, and engineers. In nutrition, understanding the link between calories and joules helps individuals manage their diet and energy intake effectively. In the power sector, converting between kilowatt-hours and British Thermal Units (BTU) is necessary for sizing heating and cooling systems for homes and offices. Physicists rely on precise energy unit conversions to calculate work, heat, and thermodynamic processes. Whether tracking fitness goals or analyzing home energy bills, accurate conversion empowers users to make better health and financial decisions.

How to Convert Calories to Joules

To convert calories to joules, use the following formula:

J = cal × 4.184

Example: 1 cal = 4.184 J

For example, 5 cal = 20.92 J, 10 cal = 41.84 J, and 100 cal = 418.4 J. For larger values, 1000 cal = 4184 J. Conversely, 1 J = 0.2390057361 cal. Our calculator above performs this conversion instantly with full precision — no rounding errors.

Common Use Cases

One thermochemical calorie: 1 cal = 4.184 J
One food Calorie (kilocalorie): 1000 cal = 4184 J
Heating 500 g of water by 1°C: 500 cal = 2092 J
Energy in a small snack (0.25 kcal): 250 cal = 1046 J

Common Mistakes to Avoid

Calorie confusion: Food 'Calories' are actually kilocalories (kcal).
Joule scale: 1 kWh is 3.6 million Joules (orders of magnitude difference).
Power vs Energy: mixing up Watts (power) and Watt-hours (energy).

Pro Tips

Food labels: Learn to read kcal; average adult needs ~2000 kcal/day.
Battery capacity: Wh = V * Ah. Useful for comparing different voltage batteries.
Efficiency: Energy cannot be created/destroyed, only converted (with some loss as heat).

What is a Calorie?

The calorie (cal) is a pre-SI unit of energy. Historically defined as the heat needed to raise 1 gram of water by 1°C. Food calories are actually kilocalories (kcal).

Calories (specifically kilocalories) are universally used in nutrition to measure the energy content of food and the energy expenditure of physical activity.

What is a Joule?

The joule (J) is the SI derived unit of energy. Defined as the work done by a force of one newton displacing an object by one meter.

Joules are used in science and engineering to measure work, energy, and heat. In nutrition, kilojoules (kJ) are used in many countries instead of calories.

Calories → Joules

Calories to Joules Formula