The Brand Coverage Chart — Bags per Square Foot at Every Target R
“How many bags of blown-in insulation do I need?” has no single answer — it has seven, one per bag on the pallet. The chart below pulls each big-box SKU’s labeled coverage (square feet per bag) at R-30, R-38, R-49, and R-60, then pre-computes what a 1200 sq ft attic actually costs at each brand’s current shelf price. Filter by the store you are standing in:
| Brand + Product | Type | Bag Size | Labeled R Max | Coverage @ R-30 | Coverage @ R-38 | Coverage @ R-49 | Coverage @ R-60 | Price / Bag | 1200 sq ft @ R-49 DIY Material Cost |
|---|---|---|---|---|---|---|---|---|---|
| GreenFiber R-60 Cellulose | Loose Cellulose | 25 lb | R-60 | ~29 | ~23 | ~18 | ~14 | $17.98 | $1,197 (67 bags) |
| GreenFiber R-49 Cellulose | Loose Cellulose | 25 lb | R-49 | ~24 | ~19 | ~15 | N/A | $19.48 | $1,558 (80 bags) |
| Owens Corning AttiCat R-49 | 0.7 PCF Loose Fiberglass | 28.5 lb | R-49 | ~23 | ~18 | ~14 | N/A | $21.98 | $1,885 (86 bags) |
| Owens Corning AttiCat R-30 | Loose Fiberglass | 28 lb | R-30 | ~33 | ~26 | N/A | N/A | $14.98 | $545 (36 bags @ R-30) |
| JM Attic Pro Cellulose | Loose Cellulose | 25 lb | R-49 | ~24 | ~19 | ~15 | N/A | $18.48 | $1,478 (80 bags) |
| Roxul Flex R-30 Rockwool | Loose Rockwool | 25 lb | R-30 | ~20 | N/A — rockwool rarely labeled above R-30 for DIY | N/A | N/A | $34.98 | $2,099 (60 bags @ R-30) |
| CertainTeed EasyFill R-49 | Loose Cellulose | 25 lb | R-49 | ~24 | ~19 | ~15 | N/A | $16.99 | $1,359 (80 bags) |
Price per bag is pre-tax, retrieved June 2025 from retailer shelf listings; verify current prices and coverage at time of purchase — retailers reprice seasonally and formulations rotate.
💡 Coverage is keyed to the TARGET R, not the bag’s headline R: an R-60 bag’s “25 sq ft” figure only applies when you blow all the way to R-60 — at an R-49 target the same bag covers about 18 sq ft because you stop sooner. The R-60 formulation is also denser (more borate, tighter packing), so the same 25 lb bag holds less volume than the R-49 recipe. Read the column that matches your target, never the headline.
How Many Bags of Blown-In Insulation for 1200 Square Feet?
Walk the default scenario every calculator on this site assumes — a 1200 sq ft attic floor at R-49 — and the brand spread becomes money. GreenFiber R-49 covers ~15 sq ft per bag, so 1200 ÷ 15 = 80 bags at $19.48, about $1,558. JM Attic Pro and CertainTeed EasyFill carry the same 15 sq ft coverage chart, landing at $1,478 and $1,359 respectively — the cheapest full-R-49 cellulose fills on the board. AttiCat R-49, with only ~14 sq ft per bag at its fluffier 0.7 PCF density, needs 86 bags and about $1,885: the per-bag price is not the per-job price.
Two edge cases bracket the chart. At the top, GreenFiber’s R-60 formulation reaches the 1200 sq ft R-49 target in just 67 bags ($1,197) because its denser pack delivers more R per inch — but blowing all the way to R-60 on the same floor takes about 85 bags at ~14 sq ft each. At the bottom, the two R-30 SKUs (AttiCat R-30 at ~33 sq ft per bag, Roxul Flex at ~20) are budget-target bags: 36 bags ($545) and 60 bags ($2,099) respectively for 1200 sq ft at R-30, the last one priced like the premium material it is.
🎯 Price the whole job, not the bag: The main attic insulation calculator sizes the scope by target R and material, then the coverage chart above converts it into pallet counts. For the depth math behind these bag numbers — R-per-inch, settling, and the ×1.15 overage — see the attic R-value chart.
Bag counts are the last step — depth is the decision that drives themPhoto: UnsplashThe Quick-Count Table — Bags by Attic Size (GreenFiber R-60 Baseline)
For any attic other than 1200 sq ft, scale linearly: bags = attic square footage ÷ per-bag coverage at your target R. The table below pre-computes the GreenFiber R-60 bag (the Home Depot 25 lb cellulose SKU) across the common attic sizes and all four targets — find your row and column, then apply the two corrections that follow.
| Attic Sq Ft | Bags @ R-30 | Bags @ R-38 | Bags @ R-49 | Bags @ R-60 |
|---|---|---|---|---|
| 500 | 17 | 22 | 28 | 36 |
| 800 | 28 | 35 | 45 | 57 |
| 1000 | 34 | 43 | 56 | 71 |
| 1200 | 41 | 52 | 67 | 85 |
| 1500 | 51 | 64 | 84 | 107 |
| 2000 | 69 | 87 | 112 | 142 |
| 2500 | 86 | 109 | 140 | 178 |
Roof-pitch correction — only for roofline applications
Formula: multiply the bag count by √(1 + (pitch/12)²). A 1200 sq ft attic floor at R-49 takes 67 bags flat — but if the same R-49 work is sprayed on a 6:12 roofline, the real surface is 13% larger, so 67 × 1.13 ≈ 76 bags. Attic floor top-ups, the overwhelming majority of DIY jobs, use the floor number with no factor at all.
✓ Verified: the 1200 sq ft row reconciles with the brand chart — 67 bags at R-49 matches the GreenFiber R-60 SKU’s pre-computed cost cell ($1,197), and 85 bags at R-60 matches its own coverage column.
The Cutout Deduction — Why Pros Buy About 4% Fewer Bags
Attic square footage is almost never all attic floor. Chimneys, skylights, and light housings occupy real area that receives no insulation, and estimating on gross square footage overbuys the pallet. The working deduction: each 8”×8” chimney flue occupies about 4 sq ft, skylights count as their actual glass area, and recessed light fixtures remove a little more depending on housing size.
On a typical 1200 sq ft attic the cutouts net out to roughly 1150 sq ft of insulatable area — which shaves about 4% off the bag count. That is 3 bags on an 80-bag R-49 order, or about $58 back at GreenFiber pricing. It is a small correction, but it is the difference between a clean pallet count and hauling returns back to the store. When in doubt, deduct the flues and skylights you can see and leave the light-fixture margin as your safety stock.
⚠️ Cutouts are not clearance zones: deducting a chimney’s footprint does not waive the fire-clearance rules around it — combustible loose fill still needs its code-listed standoff from flues and heat sources, typically handled with a rockwool collar or a metal shield. The material comparison page covers the Class A details.
Brand Notes — What the Coverage Labels Don’t Tell You
The chart’s numbers are only half the story; the other half is why they differ. Three comparisons explain most of the spread:
| Comparison | Bag-Coverage Reality | Why It Happens | Where Sold | DIY Verdict |
|---|---|---|---|---|
| GreenFiber R-60 vs R-49 | R-60 bags cover LESS at the same R-49 target | More borate + denser packing — same weight, smaller volume | Yes — both Home Depot and Lowe's | Both DIY and pro |
| AttiCat 28.5 lb vs GreenFiber 25 lb | Larger bag compensates | 0.7 PCF is less dense — more volume per pound | Home Depot exclusively | DIY standard blower works perfectly |
| Roxul Flex R-30 only | No DIY-blown rockwool above R-30 due to 100 PSI+ | No — 100 PSI rental blowers are rare and expensive | Lowe's only | Pro-only |
GreenFiber: the R-60 vs R-49 bag paradox
Shoppers searching for a greenfiber calculator usually hit the first paradox in the aisle: the R-60 bag (Home Depot) covers more area at an R-49 target than the R-49 bag (Lowe’s) does — 18 vs 15 sq ft — despite both weighing 25 lb. The R-60 recipe is packed denser with more borate, so each pound delivers more settled R. Which bag is “better” depends entirely on your target: if you are stopping at R-49, the R-60 bag gets there in 67 bags at $1,197 versus 80 bags at $1,558 — the density is amortized, not wasted; if you are going to R-60, it is the only consumer bag on the chart that gets there at all.
Owens Corning AttiCat: a bigger bag of fluffier fiber
Anyone running an attiCat calculator or an Owens Corning blown-in insulation chart search should start from the physics: AttiCat is 0.7 PCF fiberglass — less dense, more volume per pound — which is why its 28.5 lb bag compensates with bulk and why its coverage numbers (~23/18/14 sq ft) trail the cellulose bags at every target. The tradeoffs cut both ways: it needs no special machine (a standard rental blower works perfectly), it does not absorb moisture, and it settles less than cellulose. But at R-49 it costs ~$800 more in bags than the cheapest cellulose for the same 1200 sq ft — the price of buying R by volume instead of by density.
Johns Manville Attic Pro and the ProCat question
Searches for a JM insulation calculator, Johns Manville Attic Pro calculator, or procat coverage usually resolve to the same shelf: Attic Pro is the big-box attic line — 25 lb cellulose, R-49 labeled, ~15 sq ft per bag at R-49, $18.48 at Home Depot, 80 bags for 1200 sq ft ($1,478). ProCat is JM’s professional-blown fiberglass line sold through dealers with its own chart. For a DIY attic, the bag actually on the pallet is the number that matters; coverage charts are product-specific and do not transfer between lines.
TAP and the specialty cellulose lane
A TAP insulation calculator search points to a different channel entirely: TAP is thermal-acoustical pest-control cellulose, a pesticide-infused loose fill installed by licensed dealers rather than sold over the counter. There is no consumer bag chart to run — the dealer’s estimator works from the label’s printed coverage — and the premium buys pest control and sound damping on top of R-value. For a self-installed attic floor, the four DIY-stockable cellulose brands above are the practical universe.
Roxul: why the rockwool column stops at R-30
Roxul Flex is the only rockwool row on the chart, and its N/A cells are machine limitations, not marketing: loose rockwool needs a 100+ PSI blower to move, rental counters stock 3.0 HP machines at 60 PSI, and no DIY SKU is labeled above R-30. If R-38 or R-49 rockwool is the goal, that is a mineral-wool batt or a pro-blow scope — the blown-in vs batt guide prices both routes.
The pallet count is the quote — bags × price, minus cutouts, times pitchPhoto: UnsplashFrom Bags to Done — the DIY Order of Operations
The bag chart is also a logistics plan. Pallets are heavy and attic hatches are small: an 80-bag R-49 order is roughly a ton of material that has to travel bag by bag into the attic before the machine ever runs, so stage the pallet as close to the hatch as the driveway allows and budget a full day for a two-person crew — one feeding the machine, one at the hose. Big-box rental programs typically pair the blower with a minimum bag purchase; the counter will confirm the current threshold when you reserve.
Machine pacing is where first-timers lose the chart’s math: blowing too fast fluffs the fill and wastes coverage per bag, while a steady feed matches the labeled square footage. Probe the settled depth with a ruler at ten spots across the deck and average — the number that matters is depth at target R, not bags consumed. If your measurement comes up short after settling, the thickness chart tells you exactly how many more inches — and therefore bags — stand between you and the target.
Finally, reconcile the whole job the way the pros do: net square footage after cutouts, ÷ per-bag coverage at target R, × pitch factor if the work is on a roofline, and order one spare bag beyond the math. The attic insulation calculator handles the first two steps from your attic’s dimensions; this chart is the conversion table that turns its output into a pallet.
Blown-In Insulation Bag Count — FAQs
How many bags of blown-in insulation do I need for 1200 square feet?▼
At R-49, the bag count depends entirely on the bag: GreenFiber R-49 takes 80 bags ($1,558), JM Attic Pro takes 80 ($1,478), CertainTeed EasyFill takes 80 ($1,359), and AttiCat R-49 takes 86 ($1,885) because its lower R-per-inch needs more depth. For R-60 coverage, the GreenFiber R-60 bag runs about 85 bags for the same 1200 sq ft. Subtract roughly 4% if your attic has chimneys, skylights, or recessed lights — the cutout deduction explained below.
How many bags for 1000 square feet?▼
Using the GreenFiber R-60 bag as the baseline, 1000 sq ft takes about 56 bags at R-49 and 71 bags at R-60, or 34 bags at R-30 and 43 at R-38 — the same ratios as the quick-count table above. Different brands shift the count: AttiCat needs roughly 72 bags at R-49 for 1000 sq ft (14 sq ft per bag), while any of the 15-sq-ft cellulose bags need 67. Always divide your square footage by the bag label's coverage at YOUR target R, not the headline number.
What is the GreenFiber calculator and how do I use it?▼
The GreenFiber bag label carries its own coverage chart — square feet covered per bag at R-30, R-38, R-49, and R-60 — and that chart is the calculator: divide your attic's square footage by the coverage number at your target R, add 4% back for cutouts, and multiply by the pitch factor only if you are spraying a roofline. Home Depot stocks the R-60 formulation while Lowe's carries the R-49 formulation, so the bag you price determines the chart you use. The brand rows above pre-compute the 1200 sq ft result for both.
Is there an AttiCat calculator?▼
Owens Corning publishes an AttiCat coverage chart on every 28.5 lb bag, and the math is identical: attic square footage ÷ labeled coverage at your target R. For the R-49 formulation that is about 14 sq ft per bag, so a 1200 sq ft attic takes roughly 86 bags — about $1,885 at typical Home Depot pricing. The R-30 formulation covers ~33 sq ft per bag, which is why the same attic at R-30 needs only 36 bags.
What is the Owens Corning blown-in insulation chart?▼
It is the per-bag coverage table printed on AttiCat packaging: at R-30 expect ~23 sq ft, at R-38 ~18 sq ft, at R-49 ~14 sq ft per 28.5 lb bag. The chart exists because AttiCat is a 0.7 PCF fluffy fiberglass — low density means low R-per-inch (2.2–2.5 settled), which translates directly into more bags than cellulose for the same target. The full material math behind that tradeoff is in our R-value chart.
What is the difference between JM Attic Pro and ProCat?▼
Both are Johns Manville blown-in lines, but the store SKU matters more than the branding: Attic Pro is the big-box attic loose-fill (25 lb cellulose bags, R-49 labeled, ~15 sq ft per bag at R-49, $18.48 at Home Depot), while ProCat is the professional-blown fiberglass line sold through dealers with its own coverage chart. For a DIY attic job, the Attic Pro bag label is the number that matters — 80 bags covers 1200 sq ft at R-49. Verify whichever bag is actually on the pallet; coverage charts are product-specific.
What is a TAP insulation calculator?▼
TAP is thermal-acoustical pest-control cellulose — loose fill infused with a pesticide, installed by licensed dealers rather than sold over the counter. There is no consumer bag chart because the product ships through the dealer network, and the dealer's estimator does the bag math from the label's printed coverage. For a standard DIY attic, the GreenFiber, AttiCat, JM, and CertainTeed charts on this page are the ones you can actually buy and blow yourself.
Does bag coverage mean at my target R or the bag's labeled R?▼
At the LABELED R — and this trips up more DIYers than any other number on the bag. A GreenFiber R-60 bag's headline '~25 sq ft' figure applies only when you are insulating TO R-60; if your target is R-49, the same bag covers about 18 sq ft because you stop blowing sooner. The R-60 formulation is also packed denser with more borate, so the same 25 lb bag holds less volume than the R-49 version. Every column in the chart above is keyed to the target R in its header for exactly this reason.
How does roof pitch change the bag count?▼
Only for roofline applications — spraying the underside of the deck, or any job measured on the roof surface rather than the attic floor. Multiply the bag count by the pitch factor: ×1.08 for 4:12, ×1.13 for 6:12, ×1.20 for 8:12, and ×1.35 for 10:12 (the factor is √(1 + (pitch/12)²)). A 1200 sq ft attic floor at R-49 takes 67 GreenFiber bags flat, but 76 bags if the work is on a 6:12 roofline. Attic floor jobs — the vast majority of DIY top-ups — use the floor number with no factor.
Should I subtract chimneys and skylights from my square footage?▼
Yes — pros deduct about 4% for cutouts: each 8×8 inch chimney flue occupies roughly 4 sq ft, skylights count as their actual glass area, and recessed light housings remove a little more. On a 1200 sq ft attic the net is about 1150 sq ft, which shaves roughly 3 bags off an 80-bag R-49 order. It is a small correction, but it is the difference between a clean pallet count and hauling returns back to the store.
Why does the GreenFiber R-60 bag cover different area than the R-49 bag?▼
Because the two formulations pack differently. The R-60 recipe carries more boric acid fire retardant and is packed to a denser weight per cubic foot, so the same 25 lb bag releases less raw volume when blown. But that density also raises R-per-inch, so it reaches any given target at a thinner depth. Net effect at an R-49 target: the R-60 bag covers about 18 sq ft versus the R-49 bag's 15 — 67 bags doing the work of 80. Push all the way to R-60 and the picture tightens to ~14 sq ft per bag, roughly 85 bags for a 1200 sq ft attic.
Can I blow Roxul rockwool above R-30 myself?▼
Practically, no. Loose rockwool needs a 100 PSI blower to move its dense fiber, and rental counters rarely stock machines that powerful — the 3.0 HP attic blowers that handle cellulose and AttiCat simply cannot push it. That is why the chart lists Roxul Flex only to R-30 (~20 sq ft per 25 lb bag, 60 bags for a 1200 sq ft attic, about $2,099 in material) and why the material comparison flags rockwool as effectively pro-only. Above R-30, plan on a crew or pick a cellulose/fiberglass bag.