How Much Flooring for a 12x15 Room?
Boxes to order
9 boxes
180 square feet of floor, ten percent waste, boxes of 22.5 square feet.
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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.
- Floor area180 sq ft
- Coverage per box or carton22.5 sq ft
- Waste allowance10 %
Boxes to order9 boxes
| Floor area | 180 sq ft |
|---|---|
| With 10% waste | 198 sq ft |
| Boxes at 22.5 sq ft | 9 |
| Coverage bought | 202.5 sq ft |
| Left over | 22.5 sq ftkeep it for repairs |
The material list this produces
| Flooring, boxes | 9 |
|---|---|
| Underlayment, sq ft | 180 |
| Transition strips, each | 2 |
Waste allowance compared
Waste is set by how you lay it, not by how careful you are. Straight lay to herringbone, same room.
| Waste allowance | Boxes to order | With 10% waste | Left over |
|---|---|---|---|
| 5% | 9 boxes | 189 sq ft | 22.5 sq ft |
| 10% | 9 boxes | 198 sq ft | 22.5 sq ft |
| 15% | 10 boxes | 207 sq ft | 45 sq ft |
| 20% | 10 boxes | 216 sq ft | 45 sq ft |
What else matters here
A hundred and eighty square feet with ten percent is 198, nine cartons, 202.5 bought and 22.5 spare, which is exactly one carton.
If this floor is going over a concrete slab, test the slab before ordering anything. Concrete gives up moisture for months and a slab that looks and feels dry can still be driving enough vapor to cup an engineered floor or lift an adhesive. Every manufacturer sets a limit and every warranty is written around it.
The two accepted tests are a calcium chloride test, which measures pounds of moisture per thousand square feet in twenty four hours, and a relative humidity probe drilled into the slab, which is the more reliable of the two. Kits are inexpensive and the result either clears the job or tells you to put down a moisture barrier or a liquid membrane first. A plastic sheet taped down overnight is not a test, it is a hint.
What this calculator assumes
- 10 percent waste covers a straight lay in a simple rectangle. Go to 15 for a diagonal or herringbone lay, and 20 if the room is cut up with closets and angles.
- Buy the whole job in one delivery. Dye lot and batch shade move between production runs, and a single replacement box six months later will not match.
Questions people ask
How many boxes of flooring for a 12x15 room?
About 9 boxes at 22.5 square feet each, covering 180 square feet with ten percent waste.
How do I test a concrete slab for moisture?
A calcium chloride test or, better, a relative humidity probe drilled into the slab. Both have inexpensive kits, and both give a number the manufacturer's limit can be checked against.
Can I put flooring straight on concrete?
Only if the slab passes a moisture test and the product is rated for it. Otherwise a moisture barrier or a liquid applied membrane goes down first.
The flooring calculator takes any dimensions you like and hands back the same list.