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Convert Kilojoules per Kilogram-Kelvin to BTU per Pound-Rankine

Instantly convert Kilojoules per Kilogram-Kelvin (kJ/(kg·K)) to BTU per Pound-Rankine (BTU/(lb·°R)) with our free online calculator.

Reviewed by Christopher FloiedUpdated

Formula: kJ/(kg·K) to BTU/(lb·°R)multiply by 0.238846

Reference Table

Kilojoules per Kilogram-Kelvin (kJ/(kg·K))BTU per Pound-Rankine (BTU/(lb·°R))
10.238846
51.19423
102.38846
255.97115
5011.9423
10023.8846

How to Convert Kilojoules per Kilogram-Kelvin to BTU per Pound-Rankine

Formula

To convert Kilojoules per Kilogram-Kelvin (kJ/(kg·K)) to BTU per Pound-Rankine (BTU/(lb·°R)): multiply by 0.238846

Step-by-Step

  1. Start with your value in Kilojoules per Kilogram-Kelvin (kJ/(kg·K)).
  2. Multiply by 0.238846 to perform the conversion.
  3. The result is your value expressed in BTU per Pound-Rankine (BTU/(lb·°R)).

Conversion Factor

1 kJ/(kg·K) = 0.238846 BTU/(lb·°R)

Reverse Factor

1 BTU/(lb·°R) = 4.1868 kJ/(kg·K)

Worked Example

Convert 25 Kilojoules per Kilogram-Kelvin to BTU per Pound-Rankine: 25 kJ/(kg·K) = 5.97115 BTU/(lb·°R)

About Kilojoule per Kilogram-Kelvin (kJ/(kg·K))

A metric specific-entropy unit equal to exactly 1,000 J/(kg·K). kJ/(kg·K) is the dominant working unit in international engineering steam tables per IAPWS-IF97, refrigerant property tables (Lemmon-Span-Wagner Helmholtz EoS for R-134a, R-410A, R-1234yf, R-744 CO₂, ammonia R-717), and gas-turbine working-fluid property charts per VDI 4670. Standard saturated water entropy at 100°C: s_f = 1.3069 kJ/(kg·K); saturated steam at same point: s_g = 7.3549 kJ/(kg·K); the entropy of vaporization s_fg = 6.0480 kJ/(kg·K) — a direct measure of phase-change reversible heat per unit mass at that temperature (s_fg · T = h_fg at saturation). T-s diagrams (temperature-entropy thermodynamic cycle plots used for Rankine, Brayton, refrigeration, organic Rankine ORC cycles) universally use kJ/(kg·K) on the horizontal axis. Mollier h-s diagrams for steam likewise use kJ/(kg·K). The unit is dominant in Cycle-Tempo, EBSILON, GateCycle, Thermoflex, IPSEpro power-plant simulators.

About BTU per Pound-Rankine (BTU/(lb·°R))

An imperial specific-entropy unit equal to approximately 4,186.8 J/(kg·K) — numerically very close to (and traditionally used as numerically interchangeable with) the kJ/(kg·K) value, since BTU/(lb·°R) and kJ/(kg·K) have a conversion factor of exactly 4.1868 / 4.184 ≈ 1.0007 (a coincidence of imperial unit definitions). BTU/(lb·°R) is the dominant unit in US-edition steam tables (Keenan-Keyes-Hill, NIST/ASME Steam Tables US-customary printing), US-edition thermodynamics textbooks (Cengel-Boles, Moran-Shapiro-Boettner US editions; Borgnakke-Sonntag), ASHRAE Handbook tables (refrigerant data through 2024 edition still dual-lists), and US petroleum/refining process design per API and GPSA Engineering Data Book. Reference values: saturated liquid water at 70°F: s_f ≈ 0.0746 BTU/(lb·°R); saturated steam at 14.7 psia (1 atm boiling point): s_g ≈ 1.7567 BTU/(lb·°R); the entropy of vaporization at 1 atm s_fg ≈ 1.4446 BTU/(lb·°R). Convert BTU/(lb·°R) to kJ/(kg·K) by multiplying by 4.1868; the near-unity conversion is why dual-unit thermodynamics textbooks need only one decimal of precision to map between systems.

Quick Facts

  • 1 Kilojoule per Kilogram-Kelvin equals 0.238846 BTU per Pound-Rankine
  • 1 BTU per Pound-Rankine equals 4.1868 Kilojoules per Kilogram-Kelvin
  • Kilojoule per Kilogram-Kelvin is a unit of specific entropy
  • BTU per Pound-Rankine is a unit of specific entropy
  • This conversion is commonly used in turbine design, refrigeration analysis, and power plant engineering
  • The Kilojoule per Kilogram-Kelvin belongs to the metric system
  • The BTU per Pound-Rankine belongs to the imperial system

Common Kilojoule per Kilogram-Kelvin to BTU per Pound-Rankine Conversions

Kilojoules per Kilogram-Kelvin (kJ/(kg·K))BTU per Pound-Rankine (BTU/(lb·°R))
0.010.00238846
0.10.0238846
0.250.0597115
0.50.119423
10.238846
20.477692
30.716538
51.19423
102.38846
153.58269
204.77692
255.97115
5011.9423
7517.9134
10023.8846
25059.7115
500119.423
1000238.846
50001194.23
100002388.46

Understanding Kilojoules per Kilogram-Kelvin

The Kilojoule per Kilogram-Kelvin (symbol: kJ/(kg·K)) is a unit of specific entropy. A metric specific-entropy unit equal to exactly 1,000 J/(kg·K). kJ/(kg·K) is the dominant working unit in international engineering steam tables per IAPWS-IF97, refrigerant property tables (Lemmon-Span-Wagner Helmholtz EoS for R-134a, R-410A, R-1234yf, R-744 CO₂, ammonia R-717), and gas-turbine working-fluid property charts per VDI 4670. Standard saturated water entropy at 100°C: s_f = 1.3069 kJ/(kg·K); saturated steam at same point: s_g = 7.3549 kJ/(kg·K); the entropy of vaporization s_fg = 6.0480 kJ/(kg·K) — a direct measure of phase-change reversible heat per unit mass at that temperature (s_fg · T = h_fg at saturation). T-s diagrams (temperature-entropy thermodynamic cycle plots used for Rankine, Brayton, refrigeration, organic Rankine ORC cycles) universally use kJ/(kg·K) on the horizontal axis. Mollier h-s diagrams for steam likewise use kJ/(kg·K). The unit is dominant in Cycle-Tempo, EBSILON, GateCycle, Thermoflex, IPSEpro power-plant simulators.

It belongs to the metric measurement system.

Kilojoules per Kilogram-Kelvin are commonly used in turbine design, refrigeration analysis, and power plant engineering.

Understanding BTU per Pound-Rankine

The BTU per Pound-Rankine (symbol: BTU/(lb·°R)) is a unit of specific entropy. An imperial specific-entropy unit equal to approximately 4,186.8 J/(kg·K) — numerically very close to (and traditionally used as numerically interchangeable with) the kJ/(kg·K) value, since BTU/(lb·°R) and kJ/(kg·K) have a conversion factor of exactly 4.1868 / 4.184 ≈ 1.0007 (a coincidence of imperial unit definitions). BTU/(lb·°R) is the dominant unit in US-edition steam tables (Keenan-Keyes-Hill, NIST/ASME Steam Tables US-customary printing), US-edition thermodynamics textbooks (Cengel-Boles, Moran-Shapiro-Boettner US editions; Borgnakke-Sonntag), ASHRAE Handbook tables (refrigerant data through 2024 edition still dual-lists), and US petroleum/refining process design per API and GPSA Engineering Data Book. Reference values: saturated liquid water at 70°F: s_f ≈ 0.0746 BTU/(lb·°R); saturated steam at 14.7 psia (1 atm boiling point): s_g ≈ 1.7567 BTU/(lb·°R); the entropy of vaporization at 1 atm s_fg ≈ 1.4446 BTU/(lb·°R). Convert BTU/(lb·°R) to kJ/(kg·K) by multiplying by 4.1868; the near-unity conversion is why dual-unit thermodynamics textbooks need only one decimal of precision to map between systems.

It belongs to the imperial measurement system.

BTU per Pound-Rankine are commonly used in turbine design, refrigeration analysis, and power plant engineering.

Why Convert Kilojoules per Kilogram-Kelvin to BTU per Pound-Rankine?

Converting between Kilojoules per Kilogram-Kelvin and BTU per Pound-Rankine is a frequent requirement for engineers, scientists, and students working with specific entropy values. Different industries and regions favour different unit systems, so having a dependable conversion tool saves time and prevents errors in technical calculations. Whether you are verifying a specification sheet, cross-checking simulation results, or preparing a report for an international audience, accurate specific entropy conversion is essential.

Frequently Asked Questions

How do I convert Kilojoules per Kilogram-Kelvin to BTU per Pound-Rankine?

A metric specific-entropy unit equal to exactly 1,000 J/(kg·K). To convert Kilojoules per Kilogram-Kelvin to BTU per Pound-Rankine, multiply by 0.238846. For example, 25 kJ/(kg·K) equals 5.97115 BTU/(lb·°R).

How many BTU per Pound-Rankine are in 1 Kilojoule per Kilogram-Kelvin?

There are 0.238846 BTU per Pound-Rankine in 1 Kilojoule per Kilogram-Kelvin.

How many Kilojoules per Kilogram-Kelvin are in 1 BTU per Pound-Rankine?

There are 4.1868 Kilojoules per Kilogram-Kelvin in 1 BTU per Pound-Rankine.

What is the formula for Kilojoule per Kilogram-Kelvin to BTU per Pound-Rankine conversion?

The formula is: multiply by 0.238846. This means 1 kJ/(kg·K) = 0.238846 BTU/(lb·°R).

Is a Kilojoule per Kilogram-Kelvin bigger than a BTU per Pound-Rankine?

Yes. One Kilojoule per Kilogram-Kelvin is larger than one BTU per Pound-Rankine because 1 kJ/(kg·K) equals 0.238846 BTU/(lb·°R), which is less than 1.

When do you need to convert between Kilojoules per Kilogram-Kelvin and BTU per Pound-Rankine?

An imperial specific-entropy unit equal to approximately 4,186. Kilojoule per Kilogram-Kelvin and BTU per Pound-Rankine are both specific entropy units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.

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