How Much Flooring Do I Need?
Waste allowance by material and layout
| Material and layout | Add | Why |
|---|---|---|
| Laminate or vinyl plank, straight, simple room | 10% | End cuts, first and last row rips |
| Plank flooring, room with many corners or closets | 12–15% | Every obstruction creates offcuts |
| Plank flooring, diagonal or herringbone | 15–20% | Angled cuts at every wall |
| Solid or engineered hardwood | 10–15% | Plus board culling for defects and colour |
| Sheet vinyl | Pattern-dependent | Buy the full roll width; pattern repeat drives waste |
| Carpet | Roll-width dependent | Fixed roll width and seam placement dominate |
| Tile | 10–20% | See the tile calculator |
Cutting waste scales with the room's perimeter and complexity, not its area, so small awkward rooms need a bigger percentage than large open ones.
From square feet to boxes
Flooring is sold in cartons, and the coverage per carton varies between products even at the same plank size. Read the number off the carton and use it — do not compute from plank dimensions, since the carton figure already accounts for the actual milled size.
boxes = ceiling( area × (1 + waste%) ÷ coverage per box )
For a 240 sq ft room with 10% allowance and cartons covering 23.7 sq ft: 240 × 1.10 = 264, divided by 23.7 = 11.1 → 12 cartons, which is 284 sq ft. Note the box rounding pushed the real allowance to about 18% — worth checking before you also pay for a larger percentage.
Measure room by room, then total
Use the square footage calculator's add to running total button: calculate the main room, add it, change the numbers for the closet, add that, and so on. This is more accurate than measuring an overall envelope, and it also gives you the per-room numbers you need if you plan to lay in stages.
Include closets and doorway thresholds if they are getting flooring. Exclude the footprint of base cabinets and any built-in that is staying.
Reasons to buy more than the calculation
- Keep an attic stock. One unopened carton is the difference between replacing a damaged plank and replacing a floor. Dye lots and production runs change.
- Hardwood needs culling. Solid and engineered hardwood arrives with some boards you will not use in a visible area. A 10% allowance assumes you are also using the short and imperfect pieces in closets.
- Discontinued or clearance product. Buy what you might need now; there is no second trip.
- Multiple rooms in one order. Ordering together guarantees one lot across the whole job.
Two other quantities people forget
| Item | Measured by | Notes |
|---|---|---|
| Underlayment | Square feet, by the roll | Not needed with attached-pad products; required by many warranties otherwise |
| Transition strips | Each, by doorway | T-mould, reducer, or threshold per doorway |
| Baseboard or quarter round | Linear feet of perimeter | Perimeter, not area — see the linear feet guide |
| Stair nosing | Each, per tread | Often the most expensive part per piece |
Calculate the area of a room or any regular shape, add rooms into a running total, and convert the result into square yards, square meters and a material cost.
Frequently asked questions
How much extra flooring should I buy?
Ten percent over the measured area for a straight layout in a simple room, 12 to 15 percent where there are many corners and closets, and 15 to 20 percent for diagonal or herringbone layouts. Round up to whole cartons after that.
How do I convert square feet to boxes of flooring?
Divide the area including your waste allowance by the coverage printed on the carton, then round up. Use the carton figure rather than calculating from plank dimensions, because it already accounts for the actual milled size.
Should I include closets in the flooring measurement?
Yes, if you are flooring them. Measure each closet as its own small rectangle and add it to the total. Exclude the footprint of base cabinets and built-ins that are staying.
- How to Measure the Square Footage of a Room
- Square Feet, Square Yards and Square Meters: Converting Without Errors
- Linear Feet vs Square Feet: Which One Are You Buying?
- How to Calculate the Square Footage of a House