How many kilojoules are in one calorie?

One calorie equals 0.004184 kJ. The formula is kJ = cal × 0.004184.

How do I convert calories to kilojoules?

Multiply the value in calories by 0.004184. For example, 100 × 0.004184 = 0.4184 — so 100 cal = 0.4184 kJ.

How many calories are in one kilojoule?

One kilojoule equals 239.005736 cal.

Pair · linear · factor 0.004184

calories to kilojoules

calkJ

Active unit

calories · ≈ 418.4 J (base)

All units

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calcalorie100

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Frequently asked questions

A glowing emerald doughnut with a battery-and-lightning symbol at its centre, wrapped in a geometric grid, against a cosmic nebula in violet and magenta

Energy

How much energy is in a doughnut — calories, joules and kilowatt-hours

A calorie on your plate, a joule in the lab and a kilowatt-hour on your electricity bill all describe exactly the same thing: the ability to do work. One traditional doughnut holds about 407 watt-hours of energy — enough to run an efficient LED for more than a day, or charge a smartphone nearly 24 times. Here is how a single pastry ties together nutrition, physics and your power bill.

13 min