How Much Insulation for a 10x10 Room?
Bags or rolls
3 bags
The four walls of a 10 by 10 room at 8 foot ceiling height, 40 linear feet of wall, framed at 16 inches on center.
When the figures look right, the insulation material list downloads as a real PDF with your business details on it, built inside your own browser. Nothing you type is uploaded anywhere.
How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Wall or ceiling area320 sq ft
- Stud or joist spacing16 in
- Coverage per bag or roll106.8 sq ft
Bags or rolls3 bags
| Gross area | 320 sq ft |
|---|---|
| Framing factor at 16 in oc | 90% |
| Cavity area to insulate | 288 sq ft |
| Bags at 106.8 sq ft | 3 |
| Coverage bought | 320 sq ft |
The material list this produces
| Insulation batts, bags | 3 |
|---|---|
| Vapor retarder, sq ft (if required) | 320 |
Coverage per bag compared
Bag coverage is the number that decides this, and it is printed on the bag. Here is the same area at five common coverages.
| Coverage per bag | Bags or rolls | Coverage bought |
|---|---|---|
| 40 sq ft | 8 bags | 320 sq ft |
| 50 sq ft | 6 bags | 300 sq ft |
| 75 sq ft | 4 bags | 300 sq ft |
| 90 sq ft | 4 bags | 360 sq ft |
| 106.8 sq ft | 3 bags | 320 sq ft |
What else matters here
Forty linear feet of wall at eight feet tall is 320 square feet gross, 288 square feet of cavity, and three bags.
The thing to notice is that the input is wall area and not floor area. A 10 by 10 room has 100 square feet of floor and 320 square feet of wall, which is more than three times as much, and typing 100 into an insulation calculator is one of the most common ways to under order by a factor of three.
The arithmetic is perimeter times wall height. Add up the length of every wall you are actually filling, multiply by the plate height, and put that in. The ceiling, if it is getting insulated, is its own area and usually its own R value, so run it separately.
What this calculator assumes
- Framing takes up roughly 10 percent of a wall at 16 inch on center and 7 percent at 24. Cavity area is reduced accordingly, so you do not buy insulation for the studs.
- Bag coverage varies a lot by R value and width. The default is a common R-13 kraft faced batt bag; read your own bag and change it.
Questions people ask
How many bags of insulation for a 10x10 room?
Three bags for all four walls at 8 feet high, based on 320 square feet of wall and 288 square feet of cavity.
Do I use floor area or wall area for insulation?
Wall area. It is the perimeter times the wall height, and for a small room it is three or four times the floor area.
Why is the cavity area less than the wall area?
Because studs and plates take up part of the wall and they are not insulated. Framing runs about 10 percent of a wall at 16 inch on center and about 7 percent at 24 inch, so the calculator takes that off before dividing.
The insulation calculator takes any dimensions you like and hands back the same list.