U-Value & R-Value Converter
U-value is the inverse of R-value, and metric RSI is a different scale again. Enter one number and get all of them, plus the totals for a layered assembly.
Your project
Your results
- R-value (imperial)
- R-19
- U-value (imperial)
- 0.0526
- RSI (metric R)
- 3.346
- U metric
- 0.299
- Layer 2 adds
- R-6
- Assembly total with air films
- R-25.85
BTU/hr·ft²·°F
m²·K/W
W/m²·K
Polyiso rigid foam board
Includes R-0.85 for interior and exterior air films
Estimates use typical US material and labor pricing. Confirm quantities against the coverage chart on the bag before you buy.
Gear for this job
Rigid Foam Board Insulation
Multi Purpose XPS Foam Board,2 Pack 15.6x11.7X 2in Polystyrene Craft Foam Sheets,Rigid and Easy to Shape,DIY Modeling Art Projects, Party Decoration, Cosplay Prop Production, Carve,Heat Insulation
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Double-Layer Insulated Foam Panels, 3-Pack Insulation Seal Panels for Portable AC Window Vent Seal Kit, Thick Adjustable Insulation Board, Air Conditioner Window Gap Filler
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GCGOODS Window Air Conditioner Insulated Foam Panels, Winter Surround Insulation Side Panel with Top Seal Strip for Window AC Unit Indoor, White
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Fiberglass Batt Insulation R19
Owens Corning R-19 Unfaced Fiberglass Insulation 77.5 Sq.ft (15 in x 93 in) 1 Batt
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Owens Corning R-19 Fiberglass Batt Insulation Fits 2x6 Floor or Walls a Total of 10 Bags and Square Footage of 775 FT
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Owens Corning R-19 Unfaced Fiberglass Insulation 128-sq ft (24-in W x 96-in L)
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Infrared Thermometer Gun
Etekcity Infrared Thermometer Laser Temperature Gun 774 | Cooking, Pizza Oven, Griddle, BBQ, Meat, HVAC, Engine, Adjustable Emissivity, MAX Display, Surface Measurement
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TempPro TempScan Infrared Thermometer Gun for Pizza Oven Griddle HVAC | Temperature Gun with Adjustable Emissivity, Infrared Thermometer for Cooking BBQ Meat Engine, Temp Gun with -58~1022°F
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Digital Infrared Thermometer gun for cooking,BBQ,Pizza oven,Ir Thermometer with Backlight,-58℉~932℉(-50℃~500℃) Handheld Non Contact Heat Laser Temperature Gun (Not for Human)
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How this calculator works
- U = 1 ÷ R (and R = 1 ÷ U)
- RSI = R × 0.1761
- Assembly R = sum of every layer's R, plus air films
Frequently asked questions
Is a lower U-value better?
Yes. U measures heat that gets through, so lower is better — the opposite of R-value, where higher is better.
Why is metric R-value so much smaller?
Different units. R-19 imperial is RSI 3.35 metric. Multiply imperial R by 0.1761 to convert.
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R-value (imperial)
R-19