Batt Insulation R-Value Calculator
Total R-value from stacked insulation layers.
Enter your values
Enter the layer 1 r-value you are working with.
Enter the layer 2 r-value you are working with.
Enter the layer 3 r-value you are working with.
Enter the target r-value you are working with.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Total R-value
- R-19
- Target R-value
- R-38
- Shortfall/surplus
- -19
Quick answer
Total R-value is simply the sum of each insulation layer's R-value when layers are stacked without compression.
R total = R1 + R2 + ... (uncompressed)
At a glance
| What it does | Total R-value from stacked insulation layers. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Layer 1 R-value, Layer 2 R-value, Layer 3 R-value, Target R-value |
| Main output | Total R-value |
| Formula | R total = R1 + R2 + ... (uncompressed) |
| Cost | Free — no sign-up, no download |
How to use the Batt Insulation R-Value Calculator
- 1Enter the R-value printed on each batt or roll layer.
- 2Only stack layers that are not compressed, since compression lowers effective R-value.
- 3Compare the total to your climate zone's recommended R-value.
Inputs explained
- Layer 1 R-value
- Enter the layer 1 r-value you are working with.
- Layer 2 R-value
- Enter the layer 2 r-value you are working with.
- Layer 3 R-value
- Enter the layer 3 r-value you are working with.
- Target R-value
- Enter the target r-value you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Layer 1 R-value19
- Layer 2 R-value0
- Layer 3 R-value0
- Target R-value38
Results
- Total R-valueR-19
- Target R-valueR-38
- Shortfall/surplus-19
Frequently asked questions
Does compressing a batt increase R-value?
No, compressing insulation reduces its R-value because trapped air is the insulator.
Should I run insulation perpendicular?
A second layer run perpendicular to the first helps cover framing gaps (thermal bridging).
What do I need to enter into the Batt Insulation R-Value Calculator?
Just 4 values: layer 1 r-value, layer 2 r-value, layer 3 r-value, target r-value. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Batt Insulation R-Value Calculator work out the answer?
Total R-value is simply the sum of each insulation layer's R-value when layers are stacked without compression. It applies the formula R total = R1 + R2 + ... (uncompressed) and shows the working so you can check each step by hand.
Is the Batt Insulation R-Value Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.