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Work out exactly how much insulation your house needs.

Free insulation calculators for attics, walls, crawlspaces and more. Estimate R-value, batts, blown-in bags, spray foam board feet and total project cost.

Start with my attic Price a whole job

Real coverage math

Bag ratings, batt sizes and board feet — not vague square footage.

Climate-zone targets

DOE recommended R-values built into every result.

2026 cost data

Material, labor and installed totals so you can sanity-check a bid.

DIY or contractor

Compare doing it yourself against hiring it out, side by side.

Popular insulation calculators

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Insulation AreaWork out exactly how many square feet of insulation you need for a room, attic or wall assembly, including door and window deductions.R-ValueCalculate the R-value of any insulation thickness, see the DOE recommended R-value for your climate zone, and find how many more inches you need.Attic InsulationFind how many inches and how many bags of attic insulation you need to hit your target R-value, plus material and installed cost.Wall InsulationCalculate wall insulation for any stud wall: net square footage, number of stud bays, batts required and estimated cost.Blown-In BagsCalculate how many bags of blown-in cellulose or fiberglass insulation you need for your attic, plus depth, coverage per bag and cost.Batt & Roll QuantityCalculate how many batts, rolls or bags of fiberglass or mineral wool insulation your project needs, by bay size and coverage.Spray Foam Board FeetCalculate spray foam board feet, how many DIY kits you need, R-value achieved and cost for open-cell or closed-cell foam.Insulation CostEstimate insulation cost per square foot and total project price for batts, blown-in, mineral wool, rigid foam and spray foam — DIY or installed.

Recommended R-value by climate zone

Department of Energy targets for retrofit work. Find your zone, then hit the calculators.

Climate zone	Attic	Wall	Floor
Zone 1 — S. Florida, Hawaii	R-30	R-13	R-13
Zone 2 — Gulf Coast, S. Texas	R-49	R-13	R-13
Zone 3 — Southeast, S. California	R-49	R-20	R-19
Zone 4 — Mid-Atlantic, Pacific NW	R-60	R-20	R-25
Zone 5 — Midwest, New England	R-60	R-20	R-30
Zone 6 — N. Midwest, N. New England	R-60	R-21	R-30
Zone 7 — N. Minnesota, Maine	R-60	R-21	R-38
Zone 8 — Alaska interior	R-60	R-21	R-38

What insulation costs where you live

2026 installed prices per square foot for all 50 states and 60 major metros, plus the full national cost report.

Cost by state Cost by city 2026 cost report

Insulation guides

Step-by-step how-tos, material comparisons and 2026 cost breakdowns — written for people doing the work.

How-toHow to Insulate an AtticA step-by-step attic insulation guide: air sealing first, baffles, choosing batts vs blown-in, hitting R-49 to R-60, and the mistakes that waste the whole job.How-toHow to Install Batt InsulationCutting, friction-fitting, splitting around wiring and stapling batts so they actually hit their rated R-value. Includes the compression rules most DIY jobs break.How-toHow to Blow In Attic InsulationRenting the blower, calculating bags, hose handling, depth markers and two-person technique for DIY blown-in cellulose or fiberglass.How-toHow to Air Seal Before You InsulateWhere the leaks actually are, which sealant to use where, and why air sealing beats adding inches of insulation on top of a leaky ceiling.How-toHow to Find Air Leaks in Your HomeSmoke tests, infrared thermometers, thermal cameras, the hand test and blower doors — how to locate the drafts worth sealing.How-toHow to Insulate a Crawl SpaceWhether to insulate the floor above or the walls below, how to encapsulate with a vapor barrier, and what not to do in a damp crawl space.

All 34 guides →

Free mobile app

Take every insulation calculator into the attic

All 27 calculators in your pocket — on the jobsite, in the attic, offline.

Every insulation calculator, no signup
Works offline in attics and crawlspaces
Save and share results with your contractor
DOE climate-zone R-value targets built in
2026 cost data for all 50 states

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Attic insulation

31 bags

Works offline

Insulation gear worth owning

The tools and materials that show up on almost every insulation job.

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 Unfaced Fiberglass Insulation 77.5 Sq.ft (15 in x 93 in) 1 Batt

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Loctite Tite Foam Gaps & Cracks Spray Foam Sealant, 12 fl oz Can, 1 Pack - Polyurethane Expanding Insulation

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Radiant Barrier Foil Insulation Roll – 1000 Sq Ft (4 ft x 250 ft), Double-Sided Perforated Reflective Heat Shield, Heavy Duty Thermal Wrap for Homes, Garages, and Metal Buildings

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36 Pcs Attic Insulation Baffles for 24" Rafter Bays, 2" Air Channel | Black Polyethylene Rafter Vents,Improve Roof Ventilation,Prevent Insulation Blockage,Hassle-Free Installation

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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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