15 cal to J — 15 calories in joules
Exact 15 × 4.184 = 62.76
15 calories in other units
| Joules | 62.76 | J |
|---|---|---|
| Kilojoules | 0.06276 | kJ |
| Megajoules | 0.00006276 | MJ |
| Watt-hours | 0.01743333 | Wh |
| Kilowatt-hours | 0.000017433333 | kWh |
| Kilocalories | 0.015 | kcal |
| British thermal units | 0.059485 | BTU |
| Therms | 5.9485e-7 | thm |
| Foot-pounds | 46.2894 | ft·lbf |
| Electronvolts | 391,717,109,513,157,541,888 | eV |
cal to J at a glance
| Calories | Joules |
|---|---|
| 1 cal | 4.184 J |
| 2 cal | 8.368 J |
| 3 cal | 12.552 J |
| 5 cal | 20.92 J |
| 10 cal | 41.84 J |
| 20 cal | 83.68 J |
| 25 cal | 104.6 J |
| 50 cal | 209.2 J |
| 100 cal | 418.4 J |
| 250 cal | 1,046 J |
| 500 cal | 2,092 J |
| 1,000 cal | 4,184 J |
How to convert calories to joules
Multiply by 4.184 — one calorie is 4.184 joules. That factor is exact: it comes from the definition of the units rather than from a measurement, so it will not change and does not need rounding.
Working 15 × 4.184 = 62.76
In words: about sixty-three joules.
What these units are
The calorie and the joule are covered in the energy unit guide, along with every other unit on this page.
Questions
How many joules are in a calorie?
One calorie is 4.184 joules. This figure is exact — it comes from the definition of the unit, not a measurement.
What is 15 calories in joules?
15 calories is 62.76 joules. The working is 15 × 4.184 = 62.76.
Is a food Calorie the same as a calorie?
No — it is a thousand of them. The Calorie on a nutrition label is a kilocalorie, written with a capital C in principle and almost never in practice. A 250 Calorie chocolate bar holds 250,000 physics calories, or about 1,046 kilojoules, which is why European labels quote kJ alongside.
What does a kilowatt-hour actually represent?
One kilowatt drawn for one hour — a 1,000 W heater running for sixty minutes, or a 100 W bulb for ten hours. It is the unit your electricity bill is priced in, and it equals exactly 3.6 million joules.
How much energy is one BTU?
Roughly the heat needed to raise one pound of water by one degree Fahrenheit — about 1,055 joules, or the energy in a single kitchen match. Air conditioners are rated in BTU per hour, where a 12,000 BTU/h unit is one "ton" of cooling and draws around 3.5 kW of heat.
Why is the electronvolt so small?
Because it is sized for single particles: it is the energy one electron picks up crossing a one-volt potential difference. At about 1.6 × 10⁻¹⁹ joules it would be absurd for anything larger, which is precisely why particle physics uses it instead of dragging around twenty leading zeros.