BuildWellHow flooring is measured
Flooring is estimated by the square foot and bought by the box. Measure the floor, add a waste allowance for cuts, and divide by the square feet in a box, printed on the carton. Round up to whole boxes, because nobody sells half a carton.
For a rectangular room, the floor is length × width. Measure wall to wall, not baseboard to baseboard, since the flooring runs under the base or shoe molding. For an L-shaped room, split it into rectangles and add them. Closets, alcoves and the strip under a doorway go in too.
Note the transitions while you measure: where the new floor meets a different floor, a threshold, a stair nose or a tub. Each is a piece of trim to order and a few minutes of work.
The flooring formulas
- Floor area = length × width, plus closets and alcoves.
- Area with waste = floor area × (1 + waste).
- Boxes = area with waste ÷ square feet per box, rounded up.
- Coverage bought = boxes × square feet per box.
- Left over = coverage bought − floor area.
The calculator also gives the room’s perimeter, 2 × (length + width), for the shoe molding or baseboard. Subtract doorways if you want a tighter number.
How much waste to add
| Layout | A common rule of thumb |
|---|---|
| Straight lay, simple rectangular room | 5 to 10% |
| Straight lay, many corners, closets or cabinets | About 10% |
| Diagonal lay | About 15% |
| Herringbone, chevron and other patterns | 15 to 20% or more |
Waste covers the cut ends of each row, the pieces that don’t fit around obstacles, and the occasional damaged board. Long planks waste more per cut than short ones. Patterns waste more because every piece is cut.
For a straight lay in a simple room, 10% is a common allowance.
Boxes and leftovers at different waste factors
A 200 square foot room with 20 square feet in a box.
| Waste | Sq ft to cover | Boxes at 20 sq ft | Left over |
|---|---|---|---|
| 0% | 200 | 10 | 0 sq ft |
| 5% | 210 | 11 | 20 sq ft |
| 10% | 220 | 11 | 20 sq ft |
| 15% | 230 | 12 | 40 sq ft |
| 20% | 240 | 12 | 40 sq ft |
Because boxes round up, the leftover is often more than the waste you planned. That’s fine. Leave it with the client for repairs.
Worked examples
A 15 × 12 bedroom in vinyl plank
180 square feet. With 10% waste, 198 square feet. At 20 square feet a box, 9.9, so 10 boxes. You buy 200 square feet and have 20 left for repairs. The perimeter is 54 feet of shoe molding.
The same room on a diagonal
Diagonal lays waste more, so use 15%: 207 square feet. With a product that has 23.4 square feet in a box, 207 ÷ 23.4 = 8.85, so 9 boxes, or 210.6 square feet, leaving 30.6 square feet spare.
An L-shaped living room in engineered wood
The main room is 20 × 14, or 280 square feet, plus a 6 × 5 alcove, 30 square feet: 310 square feet in all. With 10% waste, 341 square feet. At 24 square feet a box, 14.2, so 15 boxes, 360 square feet, with 50 left over.
Before you install
Most of a floor’s quality comes from what’s under it.
- Flatness. Floating floors and large tiles need a flat subfloor. Check the maker’s tolerance and fix high and low spots before you start.
- Moisture. Concrete slabs and crawlspaces can push moisture into a floor. Test, and use the vapor barrier or underlayment the maker calls for.
- Acclimation. Many products, wood especially, need to sit in the room before they go down. Follow the maker’s instructions.
- Expansion gap. Floating floors and wood move with the seasons. Leave the gap the maker specifies at walls and fixed objects, and cover it with base or shoe.
- Old flooring. Carpet, pad, tack strip and old vinyl have to come out, and the floor has to be cleaned of staples and adhesive ridges.
Measuring rooms that aren’t rectangles
Split the floor into rectangles, measure each and add them. An L-shaped room is two rectangles. A room with a bay window is a rectangle plus a small one for the bay; a slightly generous rectangle is fine, since the waste covers it.
For stairs, count the treads and risers and price them as their own line. Stair nosing is ordered by the piece, and stairs take far more time per square foot than open floor.
Where several rooms get the same floor, add them together before rounding up to boxes. Rounding each room separately buys a partial box you don’t need for every room.
Common mistakes
Measuring to the baseboard. The floor goes under it. Measure to the wall.
Forgetting closets. They’re small rooms, and they’re full of cuts.
One box short. A second order can come from a different production run, with a slightly different color. Buy enough the first time.
Skipping transitions and trim. Thresholds, reducers and stair noses are ordered separately and take time to fit.
Ignoring the subfloor. Leveling compound, a layer of underlayment or a few hours of screwing down squeaks can turn up only once the old floor is out. Say how you’ll price it.
From boxes to an estimate
A flooring estimate also covers furniture moving, tear-out and disposal, subfloor repair and prep, underlayment, the floor itself, transitions, base or shoe molding and cleanup.
Tear-out, underlayment, transitions and trim each add time on top of the floor itself, so a room that needs all of them costs noticeably more than its square footage alone suggests. List them as separate lines so the client sees why.
When you estimate flooring in BuildWell, describe the rooms or add a floor plan for the measurements, and it plans each of those as its own line with labor hours. Materials are priced at stores near the job, checked within 30 days, and labor at your metro’s wage plus your overhead and markup. Every quantity, hour and price can be edited before you send it.
