Welcome to our KJ/kg·K to BTU/lb·F Converter, the most reliable and accurate online tool for converting kilojoules per kilogram per Kelvin (KJ/kg·K) to British Thermal Units per pound per degree Fahrenheit (BTU/lb·F). Here you can convert KJ/kg·K to BTU/lb·F and BTU/lb·F to KJ/kg·K.

This converter is widely used in thermodynamics, heat transfer, mechanical engineering, and HVAC systems, where energy, temperature, and mass-specific heat capacities are measured and compared between SI (metric) and Imperial (US customary) units.

Whether you’re a student, engineer, scientist, or HVAC technician, this tool simplifies complex unit conversions, saving time and reducing calculation errors.

 

What is KJ/kg·K?

KJ/kg·K (kilojoule per kilogram per Kelvin) is a SI unit used to express specific heat capacity — the amount of energy required to raise the temperature of 1 kilogram of a substance by 1 Kelvin (or 1°C).

In other words:

It tells us how much heat energy (in kilojoules) is needed to change the temperature of a given mass by one unit.

Examples:

Water has a specific heat capacity of approximately 4.186 KJ/kg·K.

Aluminum’s specific heat is about 0.897 KJ/kg·K.

This unit is standard in thermodynamic equations, energy balance calculations, and scientific experiments across industries.

 

What is BTU/lb·F?

BTU/lb·F (British Thermal Units per pound per degree Fahrenheit) is the Imperial equivalent of KJ/kg·K.

It measures the amount of heat energy (in BTUs) needed to raise the temperature of 1 pound of a substance by 1°F.

Examples:

Water: ~1.0 BTU/lb·F

Aluminum: ~0.214 BTU/lb·F

This unit is commonly used in the United States for thermal energy calculations, particularly in HVAC, power plants, and heat exchanger design.

 

Conversion Formula: KJ/kg·K to BTU/lb·F

To convert KJ/kg·K to BTU/lb·F, use the following formula:

1 KJ/kg·K = 0.2388458966275 BTU/lb·F

Formula:

$$BTU/lb\cdot F=KJ/kg\cdot K\times 0.238846$$

Example:

Convert 4.186 KJ/kg·K (specific heat of water) to BTU/lb·F:

$$4.186\times 0.238846=1.000BTU/lb\cdot F$$

That’s why 1 KJ/kg·K ≈ 0.2388 BTU/lb·F is often used as a standard engineering approximation.

 

How to Use the KJ/kg·K to BTU/lb·F Converter

Our online converter is designed for professionals and students who need quick and precise results: Here you can convert convert KJ/kg·K to BTU/lb·F and BTU/lb·F to KJ/kg·K.

Enter the value in KJ/kg·K.

Click Convert.

Instantly get the value in BTU/lb·F.

You can also reverse the conversion (BTU/lb·F → KJ/kg·K) with one click — ideal for engineers switching between metric and imperial systems.

 

Why Convert KJ/kg·K to BTU/lb·F?

Different regions and industries use different measurement systems:

Conversion is essential for:

Heat capacity calculations in thermodynamics.

Designing heat exchangers and boilers.

HVAC system efficiency analysis.

Material property comparison between SI and Imperial units.

 

Understanding the Science Behind the Conversion

The conversion between KJ/kg·K and BTU/lb·F is based on three fundamental relationships:

1 BTU = 1.055056 KJ

1 pound = 0.45359237 kilograms

1°F = 5/9 Kelvin

When combined, these relationships yield:

$$1KJ/kg\cdot K=0.238846BTU/lb\cdot F$$

and inversely:

$$1BTU/lb\cdot F=4.1868KJ/kg\cdot K$$

This is why 4.186 KJ/kg·K = 1 BTU/lb·F, which forms the basis of most thermal calculations in engineering and physics.

 

Real-World Applications of KJ/kg·K and BTU/lb·F Conversion

This unit conversion is not just theoretical — it’s crucial in many fields:

1. Engineering & Thermodynamics

Used for analyzing specific heat, energy transfer, and system efficiency in engines, turbines, and compressors.

2. HVAC Systems

HVAC engineers use BTU/lb·F to calculate air properties, cooling loads, and heat transfer rates.

3. Material Science

Scientists measure specific heat capacities to understand how materials respond to temperature changes.

4. Food & Chemical Industry

Temperature and heat flow control require energy unit conversions to maintain precision in processes.

5. Academic & Research Work

Physics, mechanical, and chemical engineering students frequently convert KJ/kg·K to BTU/lb·F in coursework and reports.

 

KJ/kg·K ↔ BTU/lb·F Conversion Table

and inversely:

 

Reverse Conversion: BTU/lb·F to KJ/kg·K

To convert BTU/lb·F → KJ/kg·K, use the inverse formula:

KJ/kg·K = BTU/lb·F × 4.1868

Example:
Convert 0.25 BTU/lb·F to KJ/kg·K:

$$0.25\times 4.1868=1.0467KJ/kg\cdot K$$

This is often used when converting data from American HVAC systems or material property charts into metric form.

 

Frequently Asked Questions (FAQs)

1. What does KJ/kg·K mean?

It measures how much heat (in kilojoules) is required to raise 1 kilogram of a substance by 1 Kelvin (or 1°C).

2. What does BTU/lb·F mean?

It’s the Imperial version, expressing how much heat (in BTUs) is needed to raise 1 pound by 1°F.

3. What is the conversion factor between KJ/kg·K and BTU/lb·F?

1 KJ/kg·K = 0.238846 BTU/lb·F
and 1 BTU/lb·F = 4.1868 KJ/kg·K

4. Is this conversion used in HVAC?

Yes! HVAC engineers frequently use it to convert air and refrigerant properties between metric and imperial systems.

5. Can I convert J/kg·K to BTU/lb·F?

Yes. Divide your J/kg·K value by 1000 (to get KJ/kg·K), then multiply by 0.238846 to get BTU/lb·F.

 

The KJ/kg·K to BTU/lb·F Converter is an essential engineering and thermodynamics tool that helps you accurately convert between metric and imperial specific heat capacity units.

From energy calculations to heat transfer designs and HVAC performance analysis, this tool provides instant, precise, and reliable results — saving time and ensuring consistency across global systems.

Whether you’re converting KJ/kg·K to BTU/lb·F, BTU/lb·F to KJ/kg·K, or working with related units like KJ/kg to BTU/lb and J/kg·K to BTU/lb·F, this tool delivers the accuracy you need for all professional and academic calculations.