Joule to Kilocalorie (J to kcal)
Result
0.000239005736 Kilocalorie
Formula
kcal = J × 0.000239005736
1 J = 0.000239005736 kcal, and 1 kcal = 4,184 J.
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 J × 0.000239005736 = 0.00023900574 kcal
- 10 J × 0.000239005736 = 0.0023900574 kcal
- 100 J × 0.000239005736 = 0.023900574 kcal
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.
Joule to Kilocalorie table
| Joule (J) | Kilocalorie (kcal) |
|---|---|
| 1 | 0.00023900574 |
| 2 | 0.00047801147 |
| 5 | 0.0011950287 |
| 10 | 0.0023900574 |
| 20 | 0.0047801147 |
| 50 | 0.011950287 |
| 100 | 0.023900574 |
| 1,000 | 0.23900574 |
The units
- Joule (J)
- A unit of energy.
- Kilocalorie (kcal)
- Kilocalorie (thermochemical): exactly 4,184 J. The "Calorie" on food labels.
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