kJ and kcal converter
Convert kilojoules and kilocalories (1 kcal = 4.184 kJ), show the share of a 2000 kcal / 8400 kJ reference intake and estimate exercise minutes with a MET formula.
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Result
kJ and kcal both ways, plus NRV share and exercise time.
Enter an energy value to convert
kcal: 0
What this tool does
- Convert kilojoules on a foreign label into the kilocalories a diet app tracks: 1 kcal = 4.184 kJ.
- See how much of the 2000 kcal / 8400 kJ reference intake a portion covers.
- Estimate workout minutes with the MET formula for a given body weight.
Example
Input
250
Output
250 大卡 = 1046 kJ = 250 kcal = 250000 cal 占每日参考摄入量（8400 kJ / 2000 kcal）的 12.452381%（按千焦计 12.5%，按大卡计） 体重 60 kg 的人做慢跑（7 MET）约需 34.013605 分钟消耗完 千焦 (kJ) = 1046 kJ 大卡 (kcal) = 250 kcal 卡 (cal) = 250000 cal 每日大卡占比 (2000 kcal) = 12.5% 每日千焦占比 (8400 kJ) = 12.452381% 慢跑消耗时长（7 MET · 60 kg） = 34.013605 分钟 换算常数：1 kcal = 4.184 kJ（精确值）；运动消耗按 MET 公式估算，属近似值。
1 kcal = 4.184 kJ (exact); the NRV follows 8400 kJ / 2000 kcal and exercise time uses a MET estimate.
Frequently asked questions
What is the exact kJ to kcal relation?
1 kcal = 4.184 kJ and 1 kJ = 0.239005736 kcal, derived from the thermochemical calorie 1 cal = 4.184 J — exact, no approximation.
How is the NRV share calculated?
The reference intake follows GB 28050: 8400 kJ or 2000 kcal per day for adults. Divide the input by that value to get the percentage.
How reliable is the exercise estimate?
It uses kcal/min = MET × 3.5 × body weight (kg) ÷ 200 with MET values from the Compendium of Physical Activities. Individual metabolism can vary by ±20%, so treat it as an estimate.
Why only 6 decimals?
Values print via Number(value.toFixed(6)): 1000 ÷ 4.184 = 239.00573613… shows as 239.005736.
Keywords：千焦大卡换算kJ kcal卡路里换算食品标签能量NRV 占比运动消耗MET热量单位