kJ to kcal Converter
Convert kilojoules to kilocalories (kJ to Calories) for food labels and diets
1 kJ = 0.239006 kcal. To convert kJ to kcal, divide the kilojoules by 4.184, so 1,000 kJ is 239 kcal (food Calories).
Kilojoules to Kilocalories converter
LiveThermochemical kilocalorie = 4.184 kJ exactly, the factor used on US and EU food labels.
- 0.94781712 BTU
- 239.00574 cal
- 737.56215 ft·lbf
- 1,000 J
- 0.001 MJ
How to convert kilojoules to kilocalories
One kilocalorie is 1,000 thermochemical calories, and each calorie is exactly 4.184 joules, so 1 kcal = 4.184 kJ. Converting kJ to kcal means dividing by that same 4.184. A kilocalorie is the unit US labels print as Calories with a capital C, so the result of this converter is directly comparable with a Nutrition Facts panel. For kilowatt-hours, BTU and the rest of the family, open the energy converter.
One wrinkle surprises people: on EU and UK labels, the kJ and kcal figures are each calculated from the nutrients using separate factors (for example 17 kJ and 4 kcal per gram of carbohydrate), so dividing the printed kJ by 4.184 can land a few kcal away from the printed kcal. Both are correct within labeling rules. For the science behind the small calorie, see the joules to calories converter. If a technical source quotes International Table kilocalories (4.1868 kJ), pick that option with the Calorie switch above.
Step by step
- Find the energy in kJ on the label (per 100 g or per serving).
- Divide it by 4.184 (or multiply by 0.239006).
- Round to the nearest whole kcal, as labels do.
- Scale by your portion if the label is per 100 g.
See it on a scale
Worked examples
A small snack bar, a typical meal-sized portion and the Australian average adult daily intake used on labels.
250 kJ ÷ 4.184 = 59.751434 kcal
= 59.751434 kcal
1,000 kJ ÷ 4.184 = 239.00574 kcal
= 239.00574 kcal
8,700 kJ ÷ 4.184 = 2,079.3499 kcal
= 2,079.3499 kcal
Why does Australia use kilojoules instead of calories?
Australia and New Zealand use kilojoules because both countries went metric, and their joint Food Standards Code requires energy on the Nutrition Information Panel in kJ, with kcal allowed only as an optional extra.
The rule sits in Standard 1.2.8 of the Australia New Zealand Food Standards Code, administered by FSANZ. The panel lists energy per serving and per 100 g (or 100 mL), and the percentage daily intake column is based on an average adult diet of 8,700 kJ.
Several Australian states also require large food chains to show kilojoules on menu boards, so kJ is the unit Australians meet when they eat out as well as when they shop.
For visitors, the fix is simple: divide the panel's kJ by 4.184, or by about 4.2 in your head, to compare with US Calories. A muesli bar serving of 600 kJ is 143 kcal, and a 3,000 kJ restaurant main is 717 kcal.
How do I convert kJ per 100 g to kcal per serving?
Multiply the kJ per 100 g by your serving weight in grams, divide by 100, then divide by 4.184: kcal per serving = kJ per 100 g × grams ÷ 100 ÷ 4.184.
Example: a milk chocolate bar labeled 2,230 kJ per 100 g, eaten as a 45 g bar, gives 2,230 × 45 ÷ 100 = 1,003.5 kJ, which is 239.8 kcal.
In a spreadsheet, with kJ per 100 g in A2 and the serving weight in grams in B2, use =A2*B2/100/4.184, and wrap it in ROUND(…,0) to match label style. Drinks work the same way per 100 mL; the mL to cups converter helps when your glass is measured in cups.
EU and UK labels may add a per-portion column, but only when the pack states the portion size and the number of portions, so check which column you are reading before you convert.
kJ to kcal conversion chart
Common kilojoule values from food labels and diet plans, rounded to one decimal kcal. 418.4 kJ is exactly 100 kcal, and 8,400 kJ and 8,700 kJ are the EU and Australian label reference figures.
| Kilojoules (kJ) | Kilocalories (kcal) |
|---|---|
| 1 kJ | 0.2 kcal |
| 10 kJ | 2.4 kcal |
| 50 kJ | 12 kcal |
| 100 kJ | 23.9 kcal |
| 150 kJ | 35.9 kcal |
| 200 kJ | 47.8 kcal |
| 250 kJ | 59.8 kcal |
| 300 kJ | 71.7 kcal |
| 400 kJ | 95.6 kcal |
| 418.4 kJ | 100 kcal |
| 500 kJ | 119.5 kcal |
| 600 kJ | 143.4 kcal |
| 700 kJ | 167.3 kcal |
| 800 kJ | 191.2 kcal |
| 900 kJ | 215.1 kcal |
| 1,000 kJ | 239 kcal |
| 1,200 kJ | 286.8 kcal |
| 1,500 kJ | 358.5 kcal |
| 2,000 kJ | 478 kcal |
| 2,500 kJ | 597.5 kcal |
| 3,000 kJ | 717 kcal |
| 4,000 kJ | 956 kcal |
| 5,000 kJ | 1,195 kcal |
| 6,000 kJ | 1,434 kcal |
| 8,400 kJ | 2,007.6 kcal |
| 8,700 kJ | 2,079.3 kcal |
| 10,000 kJ | 2,390.1 kcal |
| 12,000 kJ | 2,868.1 kcal |
Kilojoules vs kilocalories: what is the difference?
The kilojoule and the kilocalorie measure the same food energy; which one you read depends mostly on where the food was packed.
| Attribute | Kilojoules | Kilocalories |
|---|---|---|
| Symbol | kJ | kcal |
| System | SI | Nutrition (food Calorie) |
| Defined as | 1,000 J | 4,184 J |
| One unit equals | 0.23900574 kcal | 4.184 kJ |
| Name on labels | Energy (kJ) | Calories in the US and Canada; kcal in the EU and UK |
| Required on labels in | EU and UK (with kcal); Australia and New Zealand (Standard 1.2.8) | US (FDA 21 CFR 101.9) and Canada, as Calories; EU and UK next to kJ |
| Label factor for a gram of fat | 37 kJ | 9 kcal |
| Adult reference intake | 8,400 kJ (EU and UK); 8,700 kJ (Australia and New Zealand) | 2,000 kcal (EU, UK and US) |
| Rounding on labels | Whole kJ in the EU and UK | US: nearest 5 Calories up to 50, nearest 10 above 50 |
4 key differences
- One kilojoule is 0.239006 kcal, so dividing a label's kJ by 4.184 lands within the label's own rounding of the printed kcal.
- The 2,000 kcal reference diet converts to exactly 8,368 kJ, while EU and UK labels use 8,400 kJ, which is 2,007.6 kcal.
- Australian daily-intake percentages use 8,700 kJ, which is 2,079.3 kcal, about 4% more than the 2,000 kcal US basis.
- US labels never show kJ and round Calories to steps of 5 or 10, so a US figure can sit up to 5 kcal from an exact conversion.
Which countries use kJ or kcal on food labels?
EU and UK labels show both kJ and kcal, Australian and New Zealand labels must show kJ (kcal is optional), and US and Canadian labels show only Calories, which are kilocalories. The details:
- European Union and United Kingdom: energy must be declared in both kJ and kcal, per 100 g or 100 mL, under Regulation (EU) No 1169/2011 (retained in UK law). The adult reference intake is 8,400 kJ / 2,000 kcal, and "% RI" figures are calculated from it.
- Australia and New Zealand: the Food Standards Code requires kilojoules; kilocalories are optional. Labels use an average adult daily intake of 8,700 kJ, which is 2,079 kcal.
- United States and Canada: labels show Calories (kcal) only, based on a 2,000 Calorie daily value.
Because label weights are often per 100 g, remember to scale to your portion. A 30 g serving of a cereal labeled 1,600 kJ per 100 g provides 480 kJ, which is 115 kcal. The grams to ounces converter helps if your scale is in ounces, and the cups to grams converter turns cup measures into label-friendly grams.
How many kJ are in a gram of fat, protein or carbohydrate?
Under EU and UK labeling rules, a gram of fat provides 37 kJ (9 kcal), and a gram of protein or carbohydrate 17 kJ (4 kcal). These are the official conversion factors used to calculate label energy in the EU and UK. The last column shows the kJ factor divided by 4.184, which explains why the printed kcal and a straight conversion of the kJ figure rarely match exactly.
| Nutrient | kJ per gram | kcal per gram (label) | kJ factor ÷ 4.184 |
|---|---|---|---|
| Carbohydrate | 17 kJ | 4 kcal | 4.06 kcal |
| Protein | 17 kJ | 4 kcal | 4.06 kcal |
| Fat | 37 kJ | 9 kcal | 8.84 kcal |
| Alcohol (ethanol) | 29 kJ | 7 kcal | 6.93 kcal |
| Fibre | 8 kJ | 2 kcal | 1.91 kcal |
| Polyols (sugar alcohols) | 10 kJ | 2.4 kcal | 2.39 kcal |
| Organic acids | 13 kJ | 3 kcal | 3.11 kcal |
Label kilojoules as a share of daily intake
How much of the daily reference each amount represents, using the EU/UK reference intake (8,400 kJ) and the Australian average adult intake (8,700 kJ). Individual needs vary with age, size and activity.
| Energy | kcal | % of 8,400 kJ (EU/UK) | % of 8,700 kJ (AU/NZ) |
|---|---|---|---|
| 200 kJ | 48 kcal | 2.4% | 2.3% |
| 400 kJ | 96 kcal | 4.8% | 4.6% |
| 500 kJ | 120 kcal | 6% | 5.7% |
| 840 kJ | 201 kcal | 10% | 9.7% |
| 1,000 kJ | 239 kcal | 11.9% | 11.5% |
| 1,500 kJ | 359 kcal | 17.9% | 17.2% |
| 2,000 kJ | 478 kcal | 23.8% | 23% |
| 2,500 kJ | 598 kcal | 29.8% | 28.7% |
Why do cyclists count kilojoules as Calories?
Because human muscles are only about 20 to 25% efficient, the food energy burned on a ride, counted in kcal, roughly equals the work a power meter reports in kJ. At an efficiency of exactly 23.9% (1 ÷ 4.184), every kilojoule delivered to the pedals would cost 4.184 kJ of food energy, which is precisely 1 kcal, so the two numbers would match. Cycling computers report that mechanical work: a rider averaging 200 W for an hour does 720 kJ, since one watt sustained for one second is one joule. The watts to kW converter handles the power side of that sum.
So a ride showing 800 kJ of work is about 800 kcal burned, not 191 kcal. Converting the power meter's kJ with this tool gives the energy you put into the pedals, which is a different quantity. Trackers that estimate calories from heart rate are less precise than this power-based rule.
How can you convert kJ to kcal in your head?
Divide by 4, then take off about 4%. For 2,000 kJ: 2,000 ÷ 4 = 500, minus 4% = 480, close to the exact 478 kcal. Even simpler, divide by 4.2: 2,000 ÷ 4.2 = 476.2, less than 0.4% off.
- Do not divide by 1,000. kJ to kcal is not a prefix change. That rule turns kJ into MJ or cal into kcal.
- kJ is the bigger number. The kilojoule figure on a label is always about four times the kcal figure. If yours is not, one of the columns is per serving and the other per 100 g.
- Going the other way, multiply kcal by 4.184 to get kJ.
To see the same energy in electrical terms, 1 kWh is 3,600 kJ, or 860.42 kcal; the kWh to BTU converter covers that side.
Sources and further reading
The standards and references behind the numbers on this page. Links open in a new tab.
Standards and official sources
Further reading
- EnergyWikipedia
kJ to kcal FAQs
Short, exact answers to what people ask most.
How many kcal are in 1 kJ?
One kilojoule is 0.239006 kcal, about a quarter of a food Calorie.
Is kcal the same as Calories?
Yes. The Calorie with a capital C on food labels is one kilocalorie, 1,000 small calories or 4.184 kJ.
What is 8,700 kJ in Calories?
8,700 kJ is 2,079 kcal. It is the average adult daily energy intake used on Australian and New Zealand labels.
How many Calories is 2,000 kJ?
2,000 kJ equals 478 kcal, or about 478 Calories.
Why do food labels show both kJ and kcal?
EU and UK law requires both so that consumers used to either unit can read the label. Australian and New Zealand labels must show kJ and may add kcal.
Why doesn't the label kcal equal kJ divided by 4.184?
Labels calculate each figure from the nutrients using separate rounded factors, such as 37 kJ and 9 kcal per gram of fat. The two results can differ by a few kcal, and both are within the rules.
What is 500 kJ in kcal?
500 kJ equals 119.5 kcal, or about 120 Calories.
How many kilocalories is 5,000 kJ?
5,000 kJ is 1,195.03 kcal, which rounds to 1,195 Calories on a label.
How many kJ is an International Table kilocalorie?
Exactly 4.1868 kJ, so 1,000 kJ is 238.85 kcal (IT) rather than 239.01 thermochemical kcal.
Related conversions
Factors from NIST SP 811 (2008) for the thermochemical (4.184 J) and International Table (4.1868 J) calories; label rules, nutrient factors and reference intakes from Regulation (EU) No 1169/2011 (Annexes XIII and XIV), Standard 1.2.8 of the Australia New Zealand Food Standards Code (FSANZ) and FDA 21 CFR 101.9. Last updated . How we verify our numbers.