Measurement Category Hub

Energy & Work Converters & Calculators

Convert energy values between Joules, kilojoules, scientific calories, dietary kilocalories, Watt-hours, kilowatt-hours, and BTUs. Use our universal interactive energy & work calculator below or select one of our dedicated conversion shortcuts.

Energy & Work

From: Joule

(J)

Example: 1000 J

To: Kilojoule

(kJ)

e.g. 1kJ

Standard: 1 kJ = 1.0000e+3 J

Enter any number above to convert Joules to Kilojoules. Click (i) for brief unit info.

Popular Energy & Work Conversions

2 dedicated tools

Joules to Calories Converter (Thermochemical)

Convert mechanical work in Joules (J) to scientific calories (cal).

calories = Joules ÷ 4.184

Calories to Joules Converter (Thermochemical)

Convert thermochemical calories (cal) to SI Joules (J).

Joules = calories × 4.184

Supported Energy & Work Units & Standards

Unit Name	Symbol	Type / System	Relative Value
JouleBase SI	J	SI Standard Unit	1 J = 1 base
Kilojoule	kJ	Derived Unit	1 kJ = 1000 base
Calorie (Thermochemical)	cal	Derived Unit	1 cal = 4.184 base
Kilocalorie (Dietary Calorie)	kcal	Derived Unit	1 kcal = 4184 base
Watt-hour	Wh	Derived Unit	1 Wh = 3600 base
Kilowatt-hour	kWh	Derived Unit	1 kWh = 3600000 base
British Thermal Unit (ISO)	BTU	Derived Unit	1 BTU = 1055.05585262 base
Electronvolt	eV	Derived Unit	1 eV = 1.602176634e-19 base

Energy & Work FAQs

In the International System of Units (SI) or standard physical conventions, the base reference unit is Joule. All linear conversions within this category are mathematically derived from this base factor.