How much flooring do I need?
Measure each floor section, add the areas, apply a layout-appropriate waste allowance, then divide by the exact coverage printed on the carton and round up to whole boxes.
18 × 14 ft room
252 square feet before waste
The flooring calculation
Use the carton’s stated coverage, not a remembered value from another product. Carton quantities must be whole numbers, so round only after the waste-adjusted area is divided by coverage.
Box estimates for an 18 × 14 ft room
| Waste | Area to cover | 18 ft²/carton | 20 ft²/carton | 24 ft²/carton |
|---|---|---|---|---|
| 5% | 264.6 ft² | 15 boxes | 14 boxes | 12 boxes |
| 10% | 277.2 ft² | 16 boxes | 14 boxes | 12 boxes |
| 15% | 289.8 ft² | 17 boxes | 15 boxes | 13 boxes |
Coverage must come from the exact carton. Open-box return rules and dye-lot or production-lot matching vary.
Measure irregular rooms without guessing
Break an L-shaped room, hallway, closet, or connected space into rectangles. Multiply length by width for each section, then add the areas before waste. Do not subtract every cabinet or small obstruction automatically; the cuts around them may consume nearly as much material as their footprint saves.
Pattern direction matters. Diagonal layouts, large tiles, herringbone patterns, many doorways, narrow spaces, and boards that must be culled for appearance can need a larger allowance than a simple straight installation. Product instructions and the installer’s layout control.
Before buying flooring
- Measure every section. Record dimensions and keep a sketch.
- Choose the exact product. Note carton coverage, plank or tile size, and lot information.
- Set the layout. Decide direction, pattern, transitions, and starting line before selecting waste.
- Count related materials separately. Underlayment, moisture barriers, adhesive, trim, transitions, and fasteners use different coverage rules.
- Read installation instructions. Subfloor flatness, moisture, acclimation, expansion space, and environmental conditions are product-specific.
Frequently asked questions
Is 10% waste always enough?
No. It is a common planning value for straightforward layouts, but room shape, pattern, product grade, damage, and future-repair stock can change the order.
Can I combine leftover flooring from another room?
Only if it is the same compatible product and the appearance is acceptable. Confirm dimensions, locking profile, color, and production-lot differences.
Should I round square feet or boxes?
Keep the area calculation precise and round the final carton count up. Rounding every intermediate step can inflate the order.