How to Convert kJ to Calories (Formula and Examples)

By KJ to Cal Editorial Team · Updated 11 Oct 2026

The kJ to calories formula

The kJ to cal formula (also called the kJ to calorie formula) comes straight from the definition of the calorie. One calorie is 4.184 joules, so one kilocalorie is 4,184 joules, which is 4.184 kilojoules.

The kJ to calories equation is therefore:

kcal = kJ ÷ 4.184

You will sometimes see it as kcal = kJ × 0.239006 instead. That is the same equation, because 1 ÷ 4.184 = 0.239006 (rounded). Dividing by 4.184 is slightly easier to remember and avoids a rounding step.

How to convert kJ to cal, step by step

1. Read the energy in kJ. On a food label it is usually printed as "Energy" with a number followed by kJ.
2. Divide by 4.184. Use a calculator, or the converter on the home page.
3. Round sensibly. Food labels round to the nearest whole calorie, so 478.01 kcal becomes 478 kcal.
4. Label your answer. Write kcal, and if you need small calories, multiply the kcal by 1,000.

Worked examples

Notice that the calorie figure is always a bit under one quarter of the kJ figure. That observation leads to a handy shortcut.

How to calculate calories from kJ without a calculator

Dividing by 4 is easy, and 4.184 is only 4.6% bigger than 4. So a quick estimate is:

1. Divide the kJ by 4.
2. Take off roughly 4 to 5 percent of the answer.

For 1000 kJ: 1000 ÷ 4 = 250, and 4.6% of 250 is about 11.5, so the estimate is about 238.5 kcal. The exact answer is 239.01 kcal. Another shortcut is to multiply by 0.24, which is within half a percent of the exact factor.

Other names for the same method

People look for this method under many names: the kj to cal conversion, the kj to calorie conversion, the kilojoule to calorie conversion, the kj conversion to calories, the kjs to calories conversion and the conversion of kj to cal. Others ask how to calculate kj to calories, or simply want to calculate kj to calories or calculate kilojoules to calories from a food label. The wording changes but the method does not: divide by 4.184.

Convert kJ to calories in a spreadsheet

In Excel or Google Sheets, put your kilojoules in cell A2 and enter this formula in B2:

=A2/4.184

Drag it down to convert a whole column. To round to whole calories, use =ROUND(A2/4.184,0).

How to convert cal to kJ

Reverse the operation and multiply: kJ = kcal × 4.184. For example, 1800 kcal × 4.184 = 7,531.2 kJ. The calories to kJ converter does this for you.

Converting to small calories (cal)

If a problem uses the small calorie, multiply the kilojoules by 1,000 and divide by 4.184, which is the same as multiplying by about 239.006. For example, 5 kJ = 1,195.03 cal. To keep the units straight, remember that 1 kcal = 1,000 cal.

Common mistakes when converting kJ to calories

• Treating kJ and kcal as equal. They are not. 1000 kJ is only 239.01 kcal.
• Multiplying instead of dividing. kJ to kcal makes the number smaller, so if your answer grew, you multiplied.
• Mixing cal and kcal. Small calories and kilocalories differ by a factor of 1,000.
• Rounding too early. Round only at the end, especially when you add several values.
• Expecting labels to match exactly. Printed kcal and kJ are calculated separately and rounded, so a small gap is normal. See our methodology for the reason.

Last updated 11 Oct 2026. How we calculate.