Insulation R-value Calculator Online (R-value Insulation)

Last updated on by Editorial Staff

Insulation R-value Calculator

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Quick Guide to Use the Calculator

  • Step 1: Select the object type from the dropdown menu – choose between “Flat” or “Cylindrical.
  • Step 2: Fill in the required input fields based on the selected object type:
  • For “Flat” objects: Enter thickness and thermal conductivity.
  • For “Cylindrical” objects: Provide uninsulated pipe radius, insulated pipe radius, and thermal conductivity.
  • Step 3: Choose the preferred units for thickness, radius, and thermal conductivity using the provided radio buttons. make sure you have selected the same units for all input fields. For example, If you select meter for thickness, you need to select thermal conductivity unit as W/m·K, and you will get a result in m²·K/W. similarly, if you choose feet as a unit of thickness, select BTU/ft·°F·h as the thermal conductivity unit. you will get results in ft²·°F·h/BTU. Same thing for cylindrical objects also.
  • Step 4: Click the “Calculate” button for the insulation R-value.
  • Step 5: To start a new calculation, click the “Reset” button. Once you click the reset button, again you need to choose the object type for which, you want to do the calculation.


For Flat object

R-value = thickness / thermal conductivity

Cylindrical objects

R = r2 ln (r2/r1) / k


 r1 = Uninsulated pipe radius 

 r2 = Insulated pipe radius 

k = Thermal conductivity 

ln = Natural Logarithm

What is the Insulation R-value Calculator?

The Insulation R-value Calculator helps determine the insulation’s thermal resistance (R-value) for both flat and cylindrical objects.

It considers factors like thickness and thermal conductivity to provide a valuable metric for assessing insulation effectiveness.

Who Can Use This Calculator?

This calculator is suitable for engineers, architects, or anyone involved in designing or evaluating insulation for flat or cylindrical structures.

Industries That Can Use This Calculator

Benefits of Using This Calculator

  • Quick assessment of insulation effectiveness.
  • Accurate R-value calculations.
  • Facilitates informed decision-making in insulation material selection.


How is the R-value calculated for cylindrical objects?

The formula considers the ratio of insulated and uninsulated pipe radius, along with the logarithm, to determine the R-value.

Can I switch between flat and cylindrical calculations?

Yes, simply select the desired object type, and the corresponding input fields will adjust.

What are the units for the R-value?

The R-value is provided in either square meters kelvin per watt (m²·K/W) or square feet degree Fahrenheit per British Thermal Unit (ft²·°F·h/BTU).


The Insulation R-value Calculator is a versatile tool catering to professionals in various industries, offering quick and accurate insights into insulation efficiency for both flat and cylindrical structures.

It promotes energy-efficient decision-making in construction and manufacturing processes.