Flooring Calculator
How much flooring do you need? Enter the size of the room, the coverage of each box, and the extra for waste to find how many boxes to buy, and what they will cost.
Boxes of flooring
10
Check the highlighted fields to see your result.
- Area
- 180.0 ft²
- Area with waste
- 198.0 ft²
- Left over
- 20.0 ft²
- Estimated cost
- 700.00
Results are estimates for information only and do not constitute financial, medical, or legal advice.
How it works
The calculator finds the area of the room, adds any extra area you enter, and adds a percentage for waste, because flooring has to be cut at the walls and some pieces are damaged. It divides by the coverage of one box and rounds up, since boxes are sold whole. It also shows how much extra flooring is left over and, if you enter a price, the total cost.
The formulas
Area = length × width + extra area
Boxes = area × (1 + waste) ÷ coverage per box, rounded up
Worked example
A room of 15 × 12 ft, 10% waste, boxes of 20 sq ft, at 3.50 per sq ft.
- Area: 15 × 12 = 180 sq ft.
- With waste: 180 × 1.10 = 198 sq ft.
- Boxes: 198 ÷ 20 = 9.9, rounded up to 10 boxes, covering 200 sq ft (20 sq ft left over).
- Cost: 200 × 3.50 = 700.
Frequently asked questions
How much flooring do I need?
Multiply the length by the width of the room to get the area, add 10% for cuts and mistakes, and divide by the coverage of one box. A 15 × 12 ft room is 180 sq ft, so with 10% extra you need 198 sq ft, which is 10 boxes of 20 sq ft each.
How much extra should I buy?
About 10% for a straight layout, and about 15% for diagonal layouts, herringbone patterns, or rooms with many corners. Tile and stone can need more. Keeping a few spare pieces is also handy for future repairs.
Does this work for laminate, vinyl, hardwood, and tile?
Yes. Any flooring that is sold by the box works the same way. Enter the coverage printed on the box. For hardwood that is sold by the square foot or meter, enter 1 as the coverage per box to get the total area with waste.
How do I measure a room that is not a rectangle?
Divide it into rectangles. Enter the largest one in the length and width boxes and add the areas of the others in the extra area box.