For L-shaped rooms, split the room into rectangles, calculate each one, and add the results.
How to use the flooring & tile calculator
- Measure the room length and width at the widest points.
- Pick your layout. Diagonal and herringbone patterns need more extra material for cuts.
- Enter the square feet per box from the product label.
- Add your price per square foot to see the total cost.
The formula
Area: length × width.
Boxes: area × (1 + waste %) ÷ square feet per box, rounded up.
Boxes needed for common room sizes (20 sq ft boxes, 10% waste)
| Room size | Area | Boxes |
|---|---|---|
| 10 × 10 ft | 100 sq ft | 6 |
| 10 × 12 ft | 120 sq ft | 7 |
| 12 × 12 ft | 144 sq ft | 8 |
| 12 × 14 ft | 168 sq ft | 10 |
| 15 × 20 ft | 300 sq ft | 17 |
| 20 × 25 ft | 500 sq ft | 28 |
Frequently asked questions
How much extra flooring should I buy?
About 10% for a standard straight layout, and 15% or more for diagonal, herringbone or rooms with many corners.
How do I measure an L-shaped room?
Split it into two rectangles, measure each, and add the areas together before adding waste.
Do I need underlayment?
Most laminate and many vinyl floors need underlayment unless it is already attached to the planks. Check the product instructions.
How many boxes of flooring for a 12×12 room?
144 sq ft plus 10% waste is about 158 sq ft, or 8 boxes of 20 sq ft each.
Results are estimates for planning and budgeting. Always confirm measurements and product coverage before you buy, and follow local building codes.