3 cal to kJ — 3 calories in kilojoules
Exact 3 ÷ 239.005736 = 0.012552
3 calories in other units
| Joules | 12.552 | J |
|---|---|---|
| Kilojoules | 0.012552 | kJ |
| Megajoules | 0.000012552 | MJ |
| Watt-hours | 0.003486666667 | Wh |
| Kilowatt-hours | 0.000003486667 | kWh |
| Kilocalories | 0.003 | kcal |
| British thermal units | 0.011897 | BTU |
| Therms | 1.1897e-7 | thm |
| Foot-pounds | 9.25788 | ft·lbf |
| Electronvolts | 78,343,421,902,631,501,824 | eV |
cal to kJ at a glance
| Calories | Kilojoules |
|---|---|
| 1 cal | 0.004184 kJ |
| 2 cal | 0.008368 kJ |
| 3 cal | 0.012552 kJ |
| 5 cal | 0.02092 kJ |
| 10 cal | 0.04184 kJ |
| 20 cal | 0.08368 kJ |
| 25 cal | 0.1046 kJ |
| 50 cal | 0.2092 kJ |
| 100 cal | 0.4184 kJ |
| 250 cal | 1.046 kJ |
| 500 cal | 2.092 kJ |
| 1,000 cal | 4.184 kJ |
How to convert calories to kilojoules
Multiply by 0.004184 — one calorie is 0.004184 kilojoules. 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 3 ÷ 239.005736 = 0.012552
Questions
How many kilojoules are in a calorie?
One calorie is 0.004184 kilojoules. This figure is exact — it comes from the definition of the unit, not a measurement.
What is 3 calories in kilojoules?
3 calories is 0.012552 kilojoules. The working is 3 ÷ 239.005736 = 0.012552.
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.