Kilocalorie to Joule (kcal to J)
Result
4,184 Joule
Formula
J = kcal × 4,184
1 kcal = 4,184 J, and 1 J = 0.000239005736 kcal.
The joule is the SI unit of energy. The calorie used here is the thermochemical calorie, exactly 4.184 J; a kilowatt-hour is exactly 3.6 MJ; the BTU is the International Table BTU (1,055.05585262 J).
Worked examples
- 1 kcal × 4,184 = 4,184 J
- 10 kcal × 4,184 = 41,840 J
- 100 kcal × 4,184 = 418,400 J
Common mistakes
- Food "Calories" (capital C) are kilocalories: a 250 Calorie snack contains 250 kcal, or 1,046 kJ.
- kW is power and kWh is energy: a 2 kW heater running for 3 hours uses 6 kWh.
- The International Table calorie (4.1868 J) is slightly larger than the thermochemical calorie (4.184 J); engineering steam tables use the former.
Kilocalorie to Joule table
| Kilocalorie (kcal) | Joule (J) |
|---|---|
| 1 | 4,184 |
| 2 | 8,368 |
| 5 | 20,920 |
| 10 | 41,840 |
| 20 | 83,680 |
| 50 | 209,200 |
| 100 | 418,400 |
| 1,000 | 4,184,000 |
The units
- Kilocalorie (kcal)
- Kilocalorie (thermochemical): exactly 4,184 J. The "Calorie" on food labels.
- Joule (J)
- A unit of energy.
Sources for these factors
- Guide for the Use of the International System of Units (SP 811), Appendix B: conversion factors — NIST
- The International System of Units (SI Brochure), 9th edition — BIPM
Last reviewed against these sources. An automated check recomputes every factor from its definition on each build. How we check accuracy