🔥Heat Energy Converter

Convert between kcal, kJ, cal, BTU, Wh, kWh instantly

How to Use the Heat Energy Converter

Enter a value, select the source unit, and all conversions appear instantly — J, cal, kcal, kJ, MJ, BTU, Wh, and kWh at once.

Unit Overview

cal (calorie): Heat needed to raise 1 g of water by 1°C. Used in chemistry and physics. 1 cal = 4.184 J.

kcal (kilocalorie): The "Calorie" on food labels. Equal to 1,000 cal. 1 kcal = 4.184 kJ. Standard for nutrition worldwide.

kJ / MJ (kilojoule / megajoule): SI units of energy. European food labels show both kJ and kcal. 1 kJ = 0.239 kcal.

BTU (British Thermal Unit): US standard for HVAC rating — air conditioners, furnaces, and water heaters. 1 BTU ≈ 1,055 J ≈ 0.252 kcal.

Wh / kWh (watt-hour / kilowatt-hour): Electrical energy units on utility bills and battery specs. 1 kWh = 3,600 kJ = 860 kcal.

Key Conversions

1 kcal = 4.184 kJ = 3.968 BTU = 1.163 Wh  |  1 kWh = 860 kcal = 3,412 BTU  |  1 BTU = 0.252 kcal = 1.055 kJ

FAQ

How many kcal is a 2,000 Calorie diet?

Exactly 2,000 kcal = 8,368 kJ. The "Calorie" used in US nutrition labeling is the kilocalorie — they are the same unit.

How do I read an air conditioner's BTU rating?

An AC rated at 12,000 BTU/h can remove 12,000 BTUs of heat per hour ≈ 3,517 watts of cooling capacity. Larger rooms need higher BTU ratings.