Convert energy units — joules, calories, kilowatt-hours, BTU, kilojoules.
| Unit | Name | Value |
|---|---|---|
| J | Joule | 4184 |
| kJ | Kilojoule | 4.184 |
| cal | Calorie | 1000 |
| kWh | Kilowatt-hour | 0.0011622222 |
| BTU | BTU | 3.9656512 |
Formula: Joule = Kilocalorie × 4184
Multiply any kilocalorie value by 4184 to get joule.
Reverse: Kilocalorie = Joule × 0.000239
Common kilocalorie values — factor: 1 kcal = 4184 J
| Kilocalorie (kcal) | Joule (J) | Context |
|---|---|---|
| 1 kcal | 4,184 J | 1 kcal snack |
| 10 kcal | 4.184e+04 J | Small fruit |
| 50 kcal | 2.092e+05 J | Cookie |
| 100 kcal | 4.184e+05 J | Small snack |
| 200 kcal | 8.368e+05 J | Light meal |
| 500 kcal | 2.092e+06 J | Workout burn |
| 1,000 kcal | 4.184e+06 J | Large meal |
| 2,000 kcal | 8.368e+06 J | Daily intake |
| 2,500 kcal | 1.046e+07 J | Active adult day |
| 5,000 kcal | 2.092e+07 J | Marathon burn |
| 1e+04 kcal | 4.184e+07 J | Ultra marathon |
| 5e+04 kcal | 2.092e+08 J | Week intake |
| 1e+05 kcal | 4.184e+08 J | Month intake |
| 1e+06 kcal | 4.184e+09 J | Year intake |
| 1.000e+09 kcal | 4.184e+12 J | Decade |
1 kcal = 4184 J. Memorize for instant estimates.
Use 4184 as a quick mental multiplier.
Multiply result by 0.000239 to recover the original kcal value.
Prescribes daily energy intake and food portion sizes in kcal.
Calculates calorie burn during workouts and links to dietary targets.
Measures energy content of food products for nutritional labeling.
Creates weight management plans based on daily kcal targets.
Optimizes pre/during/post workout nutrition using kcal calculations.
Calculates nutritional information per serving in kcal for labels.
The kilocalorie (kcal) equals 1,000 calories or 4,184 joules, and is the unit used on food labels worldwide (often written as 'Cal' with a capital C in the US). It was standardized by the International Table calorie in 1956.
Nutritionists, dietitians, and food scientists use kcal for daily energy intake recommendations. Most adults need 2,000–2,500 kcal/day. Exercise apps, fitness trackers, and dietary plans all operate on kcal.
Interesting fact: One gram of fat yields about 9 kcal, one gram of carbohydrate or protein yields about 4 kcal. A single sugar cube (4g) contains about 16 kcal.
The joule is the SI derived unit of energy, work, and heat, defined as the energy transferred when a force of one newton moves an object one meter. It was named after James Prescott Joule, the English physicist who established the mechanical equivalent of heat in the 1840s.
The joule is universal in physics and engineering: kinetic energy (½mv²), potential energy (mgh), electrical energy (VIt), and heat are all measured in joules. One joule is the energy needed to lift a 100g apple one meter against gravity.
Interesting fact: The human heart expends about 1 joule of energy with each beat. A 60-watt light bulb uses 60 joules every second. The entire energy released by a 1-megaton nuclear weapon equals about 4.18 × 10¹⁵ joules.
Converting kilocalorie to joule is common across energy, nutrition, engineering, and science. Different sectors use different energy units — joules in physics, kcal in nutrition, kWh in electricity, and BTU in HVAC — making accurate conversion essential for cross-disciplinary work and international comparisons.
Quick reference: 5 kcal = 20,920 J and 10 kcal = 41,840 J. Reverse: 1 J = 0.000239 kcal. Exact factor: 1 kcal = 4184 J.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.