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Thermal Capacity

BTU/°FtomJ/K

Convert British thermal units per degree Fahrenheit (BTU/°F) to millijoules per kelvin (mJ/K).

Factor1 BTU/°F = 1899101 mJ/K

Converter

BTU/°F

Accepts numbers or expressions, e.g. 150 + 14.7

Result
1.89910e+6mJ/K

Rendered to 6 significant figures.

Formula

Formula
mJ/K = BTU/°F × 1899101

Multiply any value in British thermal units per degree Fahrenheit by 1899101 to obtain the value in millijoules per kelvin.

Worked example

Convert 1 BTU/°F to mJ/K.

  1. 01Start with 1 BTU/°F.
  2. 02Multiply by the conversion factor: 1 × 1899101 = 1.89910e+6 mJ/K.
Result1 BTU/°F = 1.89910e+6 mJ/K

Conversion table

BTU/°FmJ/K
11.8991e+6
23.7982e+6
59.4955e+6
101.8991e+7
203.7982e+7
509.4955e+7
1001.8991e+8
2003.7982e+8
5009.4955e+8
10001.8991e+9

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from BTU/°F to mJ/K?
1 BTU/°F equals 1899101 mJ/K. To convert, multiply the value in British thermal units per degree Fahrenheit by 1899101.
How do I convert 1 BTU/°F to mJ/K?
1 BTU/°F = 1.89910e+6 mJ/K. For any value, multiply by 1899101.
How do I convert mJ/K back to BTU/°F?
Divide by the same factor — or equivalently, multiply by 5.265651e-7. So 1 mJ/K = 5.26565e-7 BTU/°F.
When would I need to convert British thermal unit per degree Fahrenheit to millijoule per kelvin?
Thermal-capacity conversions between BTU/°F and mJ/K appear in thermal-mass analysis of bodies, calorimetry, R-C thermal-network modelling, electronics thermal capacitance and large-equipment thermal-storage sizing. J/K and kJ/K are the SI standard; MJ/K and kWh/K cover large-equipment and building thermal-mass notation; BTU/°F is the US convention; cal/K and kcal/K are common in chemistry and thermochemistry. This category is lumped heat capacity only — it does NOT include specific heat capacity (J/(kg·K), requires mass), molar heat capacity (J/(mol·K), requires molecular weight) or volumetric heat capacity, all of which are different physical quantities.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).

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