Wall Insulation Calculator
Stud walls are sold by the bay, not the square foot. Enter your wall run, height and stud spacing and this returns the bay count, batt count and net coverage after openings.
Your project
Covers cuts, compression and odd bays. 10% is the usual default.
Your results
- Net wall area
- 304 sq ft
- Stud bays
- 36 bays
- Coverage to buy
- 334 sq ft
- 8 ft batts required
- 35 pieces
- R-value at 3.5 in cavity
- R-11.2
- Estimated material cost
- $152
16 in on center
Estimates use typical US material and labor pricing. Confirm quantities against the coverage chart on the bag before you buy.
Gear for this job
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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Mineral Wool Insulation Batts
3 pk 12"x12"x2" Rockwool ProRox Mineral Wool, Replaces Owens Corning Thermafiber, BMW211-3PK-NA
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Ceramic Fiber Insulation, 1" Thick x 16" x 48", 2400F Fireproof Insulation Blanket, 3026E
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10 pk 24" x 48" x 1" Rockwool ProRox Mineral Wool, Replaces Owens Corning Thermafiber, BMW142-10PK
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Staple Gun Insulation
Upholstery Staple Gun Heavy Duty, YEAHOME 4-in-1 Stapler Gun with 4000 Staples, Manual Brad Nailer Power Adjustment Stapler Gun for Wood, Crafts, Carpentry, Decoration DIY
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Arrow T50 Heavy Duty Staple Gun Kit with 3750 Pieces T50 Staples | All Chrome Steel Stapler with 3750 Pieces T50 1/4", 3/8", 1/2" Staples, for Upholstery Professional Projects
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Bielmeier Cordless Electric Staple Gun for Light-Duty Upholstery Craft DIY | Compact Handheld, Works on Fabric Softwood Cardboard, T50 STAPLES UP TO 3/8, Rechargeable Battery, Easy Load Quick Release
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How this calculator works
- Net wall area = (length × height) − openings
- Stud bays = (length in inches) ÷ stud spacing, rounded up
- Batts = coverage to buy ÷ area of one batt
Frequently asked questions
What R-value fits in a 2x4 wall?
A 3.5-inch cavity takes R-13 standard or R-15 high-density fiberglass, or about R-15 mineral wool. A 2x6 wall (5.5 inches) takes R-19 to R-21.
Should wall batts be faced or unfaced?
In cold climates use kraft-faced batts with the paper toward the heated side. In hot-humid climates unfaced batts plus a separate air barrier is usually the better call.
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Net wall area
304 sq ft