Measuring a room for flooring sounds simple. Length times width. But the number that comes out of that calculation is the net area, and you cannot order the net area. You will run short. Every flooring installation wastes some material, and how much you waste depends on the room shape, the material, and the direction you lay it.
Here is how to measure correctly and calculate an order you can actually work with.
Start with a sketch
Before touching a tape measure, sketch the room on a piece of paper. Note every doorway, alcove, closet, and bump-out. An honest sketch prevents you from forgetting something that costs you a trip back to the store.
Measure to the wall surfaces, not to baseboards. Baseboards typically add half an inch on each side, but flooring goes under or up to the baseboard, not past it. For most purposes, measure wall to wall.
Simple rectangular rooms
Square footage = length x width
Measure the longest wall, then the wall perpendicular to it. Measure at floor level if possible, since walls lean and ceilings are not always plumb. For a room that measures 12 feet 4 inches by 14 feet 8 inches:
- 12.33 ft x 14.67 ft = 180.9 sq ft
Round up to 181 square feet, then add your waste factor.
L-shaped and irregular rooms
Break the room into rectangles on your sketch. Measure each rectangle separately, calculate the area, and add the totals.
Example: An L-shaped living and dining room.
- Living room section: 14 ft x 10 ft = 140 sq ft
- Dining room section: 14 ft x 6 ft = 84 sq ft
- Total: 224 sq ft
Then apply one waste factor to 224 sq ft. Do not apply waste separately to each section.
Closets
Measure closets separately and add them in. People often forget closets entirely. A standard reach-in closet is 2 by 5 feet (10 sq ft) and adds only a small amount to the total, but forgetting it can leave you a fraction short on a large order.
The waste factor
This is the number that saves your project. Always order more than the net square footage.
| Installation type | Waste factor to add |
|---|---|
| Straight lay, simple room | 10 percent |
| Straight lay, complex room with cuts | 15 percent |
| Diagonal lay (45 degrees) | 20 percent |
| Herringbone or chevron pattern | 25 to 30 percent |
| Small tiles or narrow planks | 15 percent minimum |
For most standard flooring jobs in rectangular rooms, 10 percent is the minimum. Fifteen percent is safer for any room with more than one doorway or an irregular wall.
Running direction and plank width
Hardwood and laminate planks run in one direction across the room. The conventional direction is parallel to the longest wall or parallel to the main light source. Planks that run away from a window look better than planks running across the window, because the end joints are in shadow rather than highlighted.
Plank width matters for waste calculation. Wide planks (5 inches and up) waste less than narrow planks (2 to 3 inches) in rooms with odd dimensions, because you need fewer cuts to cover the same area. But wide planks are less forgiving if the room is not perfectly square, since out-of-square rooms become more visible with wider boards.
Converting square footage to boxes
Flooring comes in boxes. Each box covers a specific square footage printed on the label. Divide your total-with-waste by the coverage per box, then round up to the next whole box.
For example: 224 sq ft x 1.10 (10 percent waste) = 246.4 sq ft. If each box covers 20 sq ft, you need 246.4 / 20 = 12.3 boxes. Round up to 13 boxes.
Always round up to whole boxes. Returning an unopened box is easy. Running out two planks short and finding the product is sold out or from a different dye lot is not.
Keep a box back
Set aside one box of flooring and store it in a dry location after installation is complete. Scratches, water damage, and pet accidents happen years later. Having material from the same production run means repairs are invisible instead of patchwork.
The flooring calculator handles the area, waste factor, and box count in one step. For laminate specifically, the laminate flooring calculator includes plank direction options and box size inputs so you get an exact order quantity.