Free calculator
Flooring Calculator With Waste and Boxes
Free flooring calculator: square feet with waste for straight, diagonal or herringbone layouts, and how many boxes to buy.
Feet, or feet and inches: 12, 12.5, 12' 6".
Printed on the box label.
Result
Boxes of flooring to buy
23boxes
460 sq ft in those boxes
- Floor area
- 408.0 sq ft
- Waste (10%)
- 40.8 sq ft
- Area with waste
- 448.8 sq ft
Boxes are rounded up. Keep a spare box or two from the same lot for future repairs.
How it's calculated
Flooring to buy = floor area × (1 + waste %), divided by the coverage per box and rounded up. For a 300 sq ft room with a straight lay: 300 × 1.10 = 330 sq ft, and at 20 sq ft per box that's 16.5, so buy 17 boxes.
How to use the flooring calculator
Enter each room's length and width in feet, or feet and inches (12' 6" works). Pick the layout, then type the coverage printed on your box label. The calculator adds the waste allowance, divides by the box size and rounds up to whole boxes. Add a price per square foot to see the material cost.
For an L-shaped room, enter it as two rectangles. If you have the floor plan, you can skip the tape measure: open the plan in FloorFigures and it measures every room and gives flooring with waste and boxes per room.
Waste allowance by layout
Waste covers cuts at walls, doorways and corners, offcuts that are too short to use, and the odd damaged piece.
| Layout | Typical waste | Why |
|---|---|---|
| Straight lay, rectangular rooms | 5–10% | Offcuts from one row usually start the next row. |
| Straight lay, many corners or closets | 10–12% | More cuts and more short pieces. |
| Diagonal (45°) | 15% | Every row ends in an angled cut. |
| Herringbone or chevron | 15–20% | Short pieces and angled cuts at every edge. |
| Small rooms (under 50 sq ft) | Add 5% | Offcuts are harder to reuse in a small space. |
These are common installer allowances, not rules. Patterned and wide-plank products often call for more; check the manufacturer's installation guide.
A worked example
A living room of 18' × 15' and a bedroom of 12' × 11' 6", laid straight, with 20 sq ft boxes:
| Step | Math | Result |
|---|---|---|
| Living room | 18 × 15 | 270 sq ft |
| Bedroom | 12 × 11.5 | 138 sq ft |
| Floor area | 270 + 138 | 408 sq ft |
| Add 10% waste | 408 × 1.10 | 448.8 sq ft |
| Boxes | 448.8 ÷ 20 = 22.4, rounded up | 23 boxes |
Tips for measuring
- Measure each room at its longest and widest points, and round up to the next inch.
- Include closets and the floor under doors where the flooring runs through.
- Measure hallways and landings as separate rectangles.
- Inches are fractions of a foot: 6" is 0.5 ft, 3" is 0.25 ft, 9" is 0.75 ft.
- Buy every box from the same lot or run so the color matches, and keep one spare for repairs.
Updated · FloorFigures
Questions
- How much extra flooring should I buy?
- Buy about 10% extra for a straight lay in ordinary rooms, about 15% for diagonal layouts or rooms with lots of corners, and 15–20% for herringbone or chevron patterns. Add a little more for small rooms, where offcuts are harder to reuse.
- How many boxes of flooring do I need for 500 square feet?
- At 10% waste you need 550 square feet of flooring. With boxes that cover 20 square feet, that's 27.5 boxes, so buy 28. Divide by your own box's coverage, printed on the label, and always round up.
- Do I include closets when measuring for flooring?
- Yes, if the flooring continues into them. Measure each closet as its own small rectangle and add it in. Leave out areas under fixed cabinets and islands unless the flooring goes under them.
- Should I measure to the wall or the baseboard?
- Measure wall to wall. The expansion gap and the baseboard overlap are small, and the waste allowance covers the difference.
Skip the typing. Measure the plan.
Open the floor plan in FloorFigures and every room is measured for you, with the same math per room. Try it free on a sample plan; nothing is uploaded.