Flooring Calculator

How much flooring do I need?

A flooring calculator turns room size into boxes of laminate or vinyl plank. Multiply the room’s length by its width to get square feet, then divide by the area one box covers. This calculator uses 20 sq ft per box and rounds up to whole boxes. A 15 × 12 ft room is 180 sq ft, which is exactly 9 boxes. Tick the waste box to add 10% for cuts and the order becomes 10 boxes.

Enter the room’s length and width in feet and the price per box. The calculator returns the number of boxes and the cost.

The formula in plain words

• Area = length × width
• Boxes = area ÷ 20
• With waste = boxes × 1.10
• Round up to a whole box, then multiply by price per box

Rounding happens last, so the waste allowance adds one box or two depending on how close the raw number sits to a whole box.

Worked examples

Both use $45 per box.

1. Living room, 15 × 12 ft**

• Area: 15 × 12 = 180 sq ft
• Boxes: 180 ÷ 20 = 9 boxes ($405)
• With 10% waste: 9 × 1.10 = 9.9, rounded up to 10 boxes ($450)

2. Open kitchen and hallway, 14 × 22 ft**

• Area: 14 × 22 = 308 sq ft
• Boxes: 308 ÷ 20 = 15.4, rounded up to 16 boxes ($720)
• With 10% waste: 15.4 × 1.10 = 16.94, rounded up to 17 boxes ($765)

If your boxes hold 24 sq ft instead, the same 308 sq ft is 12.8 boxes, or 14.1 with waste. That rounds up to 15 boxes, two fewer than with 20 sq ft boxes. Check the label.

Boxes by room size

At 20 sq ft per box, rounded up.

Room	Area	Boxes, no waste	Boxes, 10% waste
10 × 10 ft	100 sq ft	5	6
10 × 12 ft	120 sq ft	6	7
12 × 14 ft	168 sq ft	9	10
15 × 12 ft	180 sq ft	9	10
14 × 22 ft	308 sq ft	16	17
20 × 20 ft	400 sq ft	20	22
25 × 30 ft	750 sq ft	38	42

Choosing a waste allowance

Layout	Typical allowance
Straight planks, rectangular room	about 10%
Many corners, closets, or doorways	10–15%
Diagonal layout	about 15%
Herringbone or chevron	15–20%

The calculator’s toggle is fixed at 10%. For a higher allowance, multiply the no-waste box count yourself and round up.

How to measure

1. Measure each room separately in feet, wall to wall.
2. Include closets and the space under appliances that will be floored, such as a dishwasher opening.
3. Split L-shaped rooms into rectangles and add the areas.
4. Add hallways and transitions where the floor runs continuously between rooms.
5. Do not subtract for small fixed items such as a kitchen island base. The offcuts rarely fit elsewhere.

Let the boxes sit in the room for the time the maker specifies before you install. Laminate and some vinyl expand and shrink with temperature and humidity.

Common mistakes

• Using a generic box size. Box coverage varies widely, and it changes the count.
• Buying the exact count. Planks get damaged, and the last row often needs a full plank ripped to width.
• Mixing production lots. Color can shift between lots. Check the lot numbers on each box.
• Forgetting transitions and trim. Thresholds, reducers, and quarter-round are bought separately by the piece or foot.

Related calculators

Vinyl plank with 24 sq ft boxes is covered by the vinyl plank calculator, and solid or engineered wood by the hardwood flooring calculator. Count pad rolls with the flooring underlayment calculator, and price installation with the laminate flooring cost calculator.