Flooring Calculator

What this calculator does

It finds the floor area of a rectangular room, adds the waste allowance you choose for cuts and offcuts, and, if you enter the coverage printed on the box, tells you how many whole boxes to buy and what they cost.

Formulas

• Area = length × width
• Area to buy = area × (1 + waste% ÷ 100)
• Boxes = ⌈area to buy ÷ coverage per box⌉ (always rounded up)
• Cost = boxes × price per box

Worked examples

Bedroom: 14 ft × 12 ft, 10% waste, 23.4 sq ft per box

1. Area = 14 × 12 = 168 sq ft.
2. With waste: 168 × 1.10 = 184.8 sq ft.
3. 184.8 ÷ 23.4 ≈ 7.90, so buy 8 boxes (187.2 sq ft).

Kitchen: 4.5 m × 3.6 m, 8% waste, 2.13 m² per box

1. Area = 16.2 m²; with waste 17.496 m².
2. 17.496 ÷ 2.13 ≈ 8.21, so buy 9 boxes.

Interpreting the result

The box count is the minimum to cover the area plus your allowance. Buy all boxes from the same production lot where possible. The cost line covers flooring only, not underlayment, trim, adhesive or labor.

Common mistakes

• Rounding boxes down. Even 7.1 boxes means buying 8.
• Using another product's box coverage. Plank and tile sizes, and so coverage, vary.
• Forgetting closets, alcoves and doorway transitions. Measure them as extra rooms with the square footage calculator and add the total.

Assumptions and limitations

The room is treated as a rectangle. The waste allowance is your choice: no universal figure fits every material and layout, so the default 10% is only a starting value to adjust. Follow the manufacturer's installation instructions for expansion gaps and acclimation.

Related: area calculator, paint calculator, unit price calculator.

Frequently asked questions