Should you divide kilojoules by 4.184 or 4.2?

Dividing by 4.2 is a reasonable mental shortcut and it lands within a Calorie or two on most label values. Every row in this chart uses 4.184, the figure the calorie is defined from.

Why do the kJ and kcal figures on a label not divide out exactly?

That is normal and it is not an error on the label. Manufacturers round each declared value, and in the EU and UK the energy figures are rounded to set intervals before printing, so the two numbers are each slightly adjusted versions of the same underlying calculation. If the package already prints a Calorie or kcal figure, use that one.

Does converting kilojoules change the serving the number applies to?

No. A kilojoule figure is always attached to an amount: per 100g, per serving, or per pack. Converting it does not change what it is attached to. A label reading 840 kJ per 100g is about 201 Calories per 100g, so a 150g portion is about 301 Calories.

kJ and Cal Chart | kJ to Calories Reference

Q: How do you convert kilojoules to Calories?

Divide the kilojoule figure by 4.184. 1 Cal equals 4.184 kJ, and 1 kJ equals about 0.239 Cal. On a food label, "Calories" usually means kilocalories, so 1,552 kJ is about 371 Calories.

Q: What does 8,700 kJ mean on Australian food labels?

8,700 kJ is the reference value used on Australian and New Zealand labels for percentage daily intake. It works out to about 2,079 Calories. It is a labelling reference for an average adult, not a target calculated for you.

kJ and Cal in one line

Quick answer

kJ and Cal both measure food energy. 1 Cal equals 4.184 kJ, and 1 kJ equals about 0.239 Cal. On a food label, "Calories" usually means kilocalories, so 1,552 kJ is about 371 Calories.

Some converters divide by 4.2 instead. That is a reasonable mental shortcut and it lands within a Calorie or two on most label values, but every row in this chart uses 4.184, the figure the calorie is defined from.

If you would rather type your own numbers and scale a portion at the same time, the kJ to Calories calculator does both. This page is for looking a value up quickly.

Values people look up most

These are the exact kilojoule figures that bring people to this site, mostly copied straight off a package or a menu board. Odd-looking numbers such as 1,552 or 2,032 are usually a per-serving or per-pack energy value rather than a round per-100g one.

Frequently searched kilojoule values
Kilojoules	Exact kcal	Rounded Calories
1 kJ	0.2 kcal	0 Calories
28 kJ	6.7 kcal	7 Calories
119 kJ	28.4 kcal	28 Calories
143 kJ	34.2 kcal	34 Calories
186 kJ	44.5 kcal	44 Calories
221 kJ	52.8 kcal	53 Calories
227 kJ	54.3 kcal	54 Calories
234 kJ	55.9 kcal	56 Calories
267 kJ	63.8 kcal	64 Calories
275 kJ	65.7 kcal	66 Calories
362 kJ	86.5 kcal	87 Calories
375 kJ	89.6 kcal	90 Calories
438 kJ	104.7 kcal	105 Calories
456 kJ	109.0 kcal	109 Calories
486 kJ	116.2 kcal	116 Calories
489 kJ	116.9 kcal	117 Calories
512 kJ	122.4 kcal	122 Calories
528 kJ	126.2 kcal	126 Calories
553 kJ	132.2 kcal	132 Calories
561 kJ	134.1 kcal	134 Calories
624 kJ	149.1 kcal	149 Calories
674 kJ	161.1 kcal	161 Calories
678 kJ	162.0 kcal	162 Calories
712 kJ	170.2 kcal	170 Calories
723 kJ	172.8 kcal	173 Calories
788 kJ	188.3 kcal	188 Calories
794 kJ	189.8 kcal	190 Calories
805 kJ	192.4 kcal	192 Calories
818 kJ	195.5 kcal	196 Calories
840 kJ	200.8 kcal	201 Calories
864 kJ	206.5 kcal	207 Calories
866 kJ	207.0 kcal	207 Calories
923 kJ	220.6 kcal	221 Calories
992 kJ	237.1 kcal	237 Calories
994 kJ	237.6 kcal	238 Calories
995 kJ	237.8 kcal	238 Calories
998 kJ	238.5 kcal	239 Calories
1012 kJ	241.9 kcal	242 Calories
1130 kJ	270.1 kcal	270 Calories
1176 kJ	281.1 kcal	281 Calories
1208 kJ	288.7 kcal	289 Calories
1215 kJ	290.4 kcal	290 Calories
1325 kJ	316.7 kcal	317 Calories
1327 kJ	317.2 kcal	317 Calories
1,330 kJ	317.9 kcal	318 Calories
1552 kJ	370.9 kcal	371 Calories
1578 kJ	377.2 kcal	377 Calories
1620 kJ	387.2 kcal	387 Calories
1,650 kJ	394.4 kcal	394 Calories
1665 kJ	397.9 kcal	398 Calories
1803 kJ	430.9 kcal	431 Calories
1920 kJ	458.9 kcal	459 Calories
2032 kJ	485.7 kcal	486 Calories
2090 kJ	499.5 kcal	500 Calories
2325 kJ	555.7 kcal	556 Calories
2580 kJ	616.6 kcal	617 Calories
2800 kJ	669.2 kcal	669 Calories
3290 kJ	786.3 kcal	786 Calories
3400 kJ	812.6 kcal	813 Calories
8700 kJ	2079.3 kcal	2,079 Calories

Full kJ to Calories chart

The steps get wider as the numbers get larger, because label values above about 2,000 kJ are usually whole packs or full-day figures where a few Calories either way changes nothing. For anything between two rows, divide by 4.184 or use the lookup box above.

10 to 490 kJ, in steps of 10
Kilojoules	Exact kcal	Rounded Calories
10 kJ	2.4 kcal	2 Calories
20 kJ	4.8 kcal	5 Calories
30 kJ	7.2 kcal	7 Calories
40 kJ	9.6 kcal	10 Calories
50 kJ	12.0 kcal	12 Calories
60 kJ	14.3 kcal	14 Calories
70 kJ	16.7 kcal	17 Calories
80 kJ	19.1 kcal	19 Calories
90 kJ	21.5 kcal	22 Calories
100 kJ	23.9 kcal	24 Calories
110 kJ	26.3 kcal	26 Calories
120 kJ	28.7 kcal	29 Calories
130 kJ	31.1 kcal	31 Calories
140 kJ	33.5 kcal	33 Calories
150 kJ	35.9 kcal	36 Calories
160 kJ	38.2 kcal	38 Calories
170 kJ	40.6 kcal	41 Calories
180 kJ	43.0 kcal	43 Calories
190 kJ	45.4 kcal	45 Calories
200 kJ	47.8 kcal	48 Calories
210 kJ	50.2 kcal	50 Calories
220 kJ	52.6 kcal	53 Calories
230 kJ	55.0 kcal	55 Calories
240 kJ	57.4 kcal	57 Calories
250 kJ	59.8 kcal	60 Calories
260 kJ	62.1 kcal	62 Calories
270 kJ	64.5 kcal	65 Calories
280 kJ	66.9 kcal	67 Calories
290 kJ	69.3 kcal	69 Calories
300 kJ	71.7 kcal	72 Calories
310 kJ	74.1 kcal	74 Calories
320 kJ	76.5 kcal	76 Calories
330 kJ	78.9 kcal	79 Calories
340 kJ	81.3 kcal	81 Calories
350 kJ	83.7 kcal	84 Calories
360 kJ	86.0 kcal	86 Calories
370 kJ	88.4 kcal	88 Calories
380 kJ	90.8 kcal	91 Calories
390 kJ	93.2 kcal	93 Calories
400 kJ	95.6 kcal	96 Calories
410 kJ	98.0 kcal	98 Calories
420 kJ	100.4 kcal	100 Calories
430 kJ	102.8 kcal	103 Calories
440 kJ	105.2 kcal	105 Calories
450 kJ	107.6 kcal	108 Calories
460 kJ	109.9 kcal	110 Calories
470 kJ	112.3 kcal	112 Calories
480 kJ	114.7 kcal	115 Calories
490 kJ	117.1 kcal	117 Calories

500 to 990 kJ, in steps of 10
Kilojoules	Exact kcal	Rounded Calories
500 kJ	119.5 kcal	120 Calories
510 kJ	121.9 kcal	122 Calories
520 kJ	124.3 kcal	124 Calories
530 kJ	126.7 kcal	127 Calories
540 kJ	129.1 kcal	129 Calories
550 kJ	131.5 kcal	131 Calories
560 kJ	133.8 kcal	134 Calories
570 kJ	136.2 kcal	136 Calories
580 kJ	138.6 kcal	139 Calories
590 kJ	141.0 kcal	141 Calories
600 kJ	143.4 kcal	143 Calories
610 kJ	145.8 kcal	146 Calories
620 kJ	148.2 kcal	148 Calories
630 kJ	150.6 kcal	151 Calories
640 kJ	153.0 kcal	153 Calories
650 kJ	155.4 kcal	155 Calories
660 kJ	157.7 kcal	158 Calories
670 kJ	160.1 kcal	160 Calories
680 kJ	162.5 kcal	163 Calories
690 kJ	164.9 kcal	165 Calories
700 kJ	167.3 kcal	167 Calories
710 kJ	169.7 kcal	170 Calories
720 kJ	172.1 kcal	172 Calories
730 kJ	174.5 kcal	174 Calories
740 kJ	176.9 kcal	177 Calories
750 kJ	179.3 kcal	179 Calories
760 kJ	181.6 kcal	182 Calories
770 kJ	184.0 kcal	184 Calories
780 kJ	186.4 kcal	186 Calories
790 kJ	188.8 kcal	189 Calories
800 kJ	191.2 kcal	191 Calories
810 kJ	193.6 kcal	194 Calories
820 kJ	196.0 kcal	196 Calories
830 kJ	198.4 kcal	198 Calories
840 kJ	200.8 kcal	201 Calories
850 kJ	203.2 kcal	203 Calories
860 kJ	205.5 kcal	206 Calories
870 kJ	207.9 kcal	208 Calories
880 kJ	210.3 kcal	210 Calories
890 kJ	212.7 kcal	213 Calories
900 kJ	215.1 kcal	215 Calories
910 kJ	217.5 kcal	217 Calories
920 kJ	219.9 kcal	220 Calories
930 kJ	222.3 kcal	222 Calories
940 kJ	224.7 kcal	225 Calories
950 kJ	227.1 kcal	227 Calories
960 kJ	229.4 kcal	229 Calories
970 kJ	231.8 kcal	232 Calories
980 kJ	234.2 kcal	234 Calories
990 kJ	236.6 kcal	237 Calories

1,000 to 1,980 kJ, in steps of 20
Kilojoules	Exact kcal	Rounded Calories
1000 kJ	239.0 kcal	239 Calories
1020 kJ	243.8 kcal	244 Calories
1040 kJ	248.6 kcal	249 Calories
1060 kJ	253.3 kcal	253 Calories
1080 kJ	258.1 kcal	258 Calories
1100 kJ	262.9 kcal	263 Calories
1120 kJ	267.7 kcal	268 Calories
1140 kJ	272.5 kcal	272 Calories
1160 kJ	277.2 kcal	277 Calories
1180 kJ	282.0 kcal	282 Calories
1200 kJ	286.8 kcal	287 Calories
1220 kJ	291.6 kcal	292 Calories
1240 kJ	296.4 kcal	296 Calories
1260 kJ	301.1 kcal	301 Calories
1280 kJ	305.9 kcal	306 Calories
1300 kJ	310.7 kcal	311 Calories
1320 kJ	315.5 kcal	315 Calories
1340 kJ	320.3 kcal	320 Calories
1360 kJ	325.0 kcal	325 Calories
1380 kJ	329.8 kcal	330 Calories
1400 kJ	334.6 kcal	335 Calories
1420 kJ	339.4 kcal	339 Calories
1440 kJ	344.2 kcal	344 Calories
1460 kJ	348.9 kcal	349 Calories
1480 kJ	353.7 kcal	354 Calories
1500 kJ	358.5 kcal	359 Calories
1520 kJ	363.3 kcal	363 Calories
1540 kJ	368.1 kcal	368 Calories
1560 kJ	372.8 kcal	373 Calories
1580 kJ	377.6 kcal	378 Calories
1600 kJ	382.4 kcal	382 Calories
1620 kJ	387.2 kcal	387 Calories
1640 kJ	392.0 kcal	392 Calories
1660 kJ	396.7 kcal	397 Calories
1680 kJ	401.5 kcal	402 Calories
1700 kJ	406.3 kcal	406 Calories
1720 kJ	411.1 kcal	411 Calories
1740 kJ	415.9 kcal	416 Calories
1760 kJ	420.7 kcal	421 Calories
1780 kJ	425.4 kcal	425 Calories
1800 kJ	430.2 kcal	430 Calories
1820 kJ	435.0 kcal	435 Calories
1840 kJ	439.8 kcal	440 Calories
1860 kJ	444.6 kcal	445 Calories
1880 kJ	449.3 kcal	449 Calories
1900 kJ	454.1 kcal	454 Calories
1920 kJ	458.9 kcal	459 Calories
1940 kJ	463.7 kcal	464 Calories
1960 kJ	468.5 kcal	468 Calories
1980 kJ	473.2 kcal	473 Calories

2,000 to 4,900 kJ, in steps of 100
Kilojoules	Exact kcal	Rounded Calories
2000 kJ	478.0 kcal	478 Calories
2100 kJ	501.9 kcal	502 Calories
2200 kJ	525.8 kcal	526 Calories
2300 kJ	549.7 kcal	550 Calories
2400 kJ	573.6 kcal	574 Calories
2500 kJ	597.5 kcal	598 Calories
2600 kJ	621.4 kcal	621 Calories
2700 kJ	645.3 kcal	645 Calories
2800 kJ	669.2 kcal	669 Calories
2900 kJ	693.1 kcal	693 Calories
3000 kJ	717.0 kcal	717 Calories
3100 kJ	740.9 kcal	741 Calories
3200 kJ	764.8 kcal	765 Calories
3300 kJ	788.7 kcal	789 Calories
3400 kJ	812.6 kcal	813 Calories
3500 kJ	836.5 kcal	837 Calories
3600 kJ	860.4 kcal	860 Calories
3700 kJ	884.3 kcal	884 Calories
3800 kJ	908.2 kcal	908 Calories
3900 kJ	932.1 kcal	932 Calories
4000 kJ	956.0 kcal	956 Calories
4100 kJ	979.9 kcal	980 Calories
4200 kJ	1003.8 kcal	1,004 Calories
4300 kJ	1027.7 kcal	1,028 Calories
4400 kJ	1051.6 kcal	1,052 Calories
4500 kJ	1075.5 kcal	1,076 Calories
4600 kJ	1099.4 kcal	1,099 Calories
4700 kJ	1123.3 kcal	1,123 Calories
4800 kJ	1147.2 kcal	1,147 Calories
4900 kJ	1171.1 kcal	1,171 Calories

5,000 to 10,000 kJ, in steps of 250
Kilojoules	Exact kcal	Rounded Calories
5000 kJ	1195.0 kcal	1,195 Calories
5250 kJ	1254.8 kcal	1,255 Calories
5500 kJ	1314.5 kcal	1,315 Calories
5750 kJ	1374.3 kcal	1,374 Calories
6000 kJ	1434.0 kcal	1,434 Calories
6250 kJ	1493.8 kcal	1,494 Calories
6500 kJ	1553.5 kcal	1,554 Calories
6750 kJ	1613.3 kcal	1,613 Calories
7000 kJ	1673.0 kcal	1,673 Calories
7250 kJ	1732.8 kcal	1,733 Calories
7500 kJ	1792.5 kcal	1,793 Calories
7750 kJ	1852.3 kcal	1,852 Calories
8000 kJ	1912.0 kcal	1,912 Calories
8250 kJ	1971.8 kcal	1,972 Calories
8500 kJ	2031.5 kcal	2,032 Calories
8750 kJ	2091.3 kcal	2,091 Calories
9000 kJ	2151.1 kcal	2,151 Calories
9250 kJ	2210.8 kcal	2,211 Calories
9500 kJ	2270.6 kcal	2,271 Calories
9750 kJ	2330.3 kcal	2,330 Calories
10000 kJ	2390.1 kcal	2,390 Calories

Values above 10,000 kJ are not single servings. They are day totals, multi-serve packs, or bulk catering figures, so the steps widen again; anything between two rows still divides by 4.184.

10,500 to 20,000 kJ, in steps of 500
Kilojoules	Exact kcal	Rounded Calories
10,500 kJ	2509.6 kcal	2,510 Calories
11,000 kJ	2629.1 kcal	2,629 Calories
11,500 kJ	2748.6 kcal	2,749 Calories
12,000 kJ	2868.1 kcal	2,868 Calories
12,500 kJ	2987.6 kcal	2,988 Calories
13,000 kJ	3107.1 kcal	3,107 Calories
13,500 kJ	3226.6 kcal	3,227 Calories
14,000 kJ	3346.1 kcal	3,346 Calories
14,500 kJ	3465.6 kcal	3,466 Calories
15,000 kJ	3585.1 kcal	3,585 Calories
15,500 kJ	3704.6 kcal	3,705 Calories
16,000 kJ	3824.1 kcal	3,824 Calories
16,500 kJ	3943.6 kcal	3,944 Calories
17,000 kJ	4063.1 kcal	4,063 Calories
17,500 kJ	4182.6 kcal	4,183 Calories
18,000 kJ	4302.1 kcal	4,302 Calories
18,500 kJ	4421.6 kcal	4,422 Calories
19,000 kJ	4541.1 kcal	4,541 Calories
19,500 kJ	4660.6 kcal	4,661 Calories
20,000 kJ	4780.1 kcal	4,780 Calories

Why the label's two numbers may not divide out

Plenty of packages print both units, and people notice that the kJ figure divided by 4.184 does not quite equal the printed kcal. That is normal, and it is not an error on the label.

The reason is that the two figures are rounded independently. A manufacturer works out the energy value, then rounds the kJ figure to a whole number and the kcal figure to a whole number separately. Rounding the same underlying value twice is what pulls the pair apart. Say the true value comes to 835.4 kJ and 199.6 kcal. The pack prints 835 and 200. Convert that printed 200 kcal back and you get 836.8 kJ, which is not the 835 on the panel. Nothing has gone wrong; you converted a number that had already been rounded.

A practical rule: if the package already prints a Calorie or kcal figure, use that one. Convert only when the label gives kilojoules alone, which is common on Australian and New Zealand packaging.

The kilojoules to Calories guide goes through the naming convention and the rounding in more detail.

Check what the number is per

This is the step that unit converters skip, and it changes the answer far more than the conversion factor does. A kilojoule figure is always attached to an amount: per 100g, per serving, or per pack. Converting it does not change what it is attached to.

Say a label reads 840 kJ per 100g. That is about 201 Calories per 100g. If you ate 150g, the portion is about 301 Calories, not 201. Getting the portion right moves the number by 100 Calories here, while the choice between dividing by 4.184 and 4.2 moves it by about two.

Australian and New Zealand panels usually show a per-serve column beside a per-100g column, and the serving size is set by the manufacturer rather than by how much you poured. Read the column heading before you copy the number. If you also need protein, carbohydrate, and fat scaled to your portion, use the nutrition per 100g calculator.

Where 8,700 kJ comes from

8,700 kJ shows up constantly in searches because it is the reference value used on Australian and New Zealand labels for percentage daily intake. It works out to about 2,079 Calories.

It is a labelling reference for an average adult, not a target calculated for you. Your own maintenance level depends on body size, age, and how much you move, and it shifts over time. If you want an estimate based on your own numbers, the TDEE calculator gives a starting point and the maintenance calories guide explains how much weight to put on it. To stay in kilojoules rather than converting, the daily kilojoule intake calculator answers in kJ and compares the result with the 8,700 figure directly.

What this chart will not tell you

It converts an energy value. It does not check whether the label is right, work out protein, carbohydrate, or fat, or decide how much you should eat. Rows are rounded for reading, so a printed label value beats a chart lookup whenever you have one.

This page is general information for adults, not dietary advice. Speak with a qualified clinician or registered dietitian for personal guidance, and stop tracking if it starts causing distress or compulsive checking.

Source note

The 4.184 factor comes from NIST's definition of the calorie. The FDA explains how Calories on the Nutrition Facts label are declared per serving. NHS guidance covers labels that carry both kilojoules and kilocalories. EU Regulation 1169/2011 sets the units for the nutrition declaration, while the rounding that separates the two printed figures follows the European Commission tolerance guidance, and FSANZ documents the nutrition information panel and the 8,700 kJ daily intake reference.