Enter your room size and the square feet in one box to see how many boxes of laminate, vinyl plank or wood flooring to buy, plus underlayment and baseboard.
Quick answers
Boxes of flooring = room area × (1 + extra) ÷ square feet per box, rounded up. Home Depot suggests adding 5 to 10% extra for waste.
A 12 × 15 ft room is 180 sq ft. With 10% extra that is 198 sq ft: 10 boxes of 20 sq ft.
Baseboard = room perimeter minus doorways. A 12 × 15 ft room has 54 ft of wall, so about 48 ft of baseboard with two 3 ft doorways.
How to use the flooring calculator
Measure the room wall to wall at its longest and widest points. For several rooms or an L-shape, add the areas and enter the total.
Enter the square feet per box from the label. It differs by brand and plank size.
Keep 10% extra unless the installation guide for your floor says otherwise.
The formula
Boxes = area × (1 + extra%) ÷ sq ft per box, rounded up. Baseboard = 2 × (length + width) − 3 ft per doorway. Underlayment rolls = area ÷ roll coverage, rounded up.
Worked example: a 12 × 15 ft room
12 × 15 = 180 sq ft. With 10% extra: 198 sq ft ÷ 20 sq ft per box = 9.9, so buy 10 boxes (200 sq ft). Underlayment: 2 rolls of 100 sq ft. Baseboard: 54 ft of wall minus two 3 ft doorways = 48 ft.
Boxes for common room sizes
10% extra included.
Room
Area
20 sq ft boxes
24 sq ft boxes
10 × 10 ft bedroom
100 sq ft
6
5
12 × 12 ft bedroom
144 sq ft
8
7
12 × 15 ft room
180 sq ft
10
9
15 × 20 ft living room
300 sq ft
17
14
20 × 25 ft open plan
500 sq ft
28
23
Common questions
How much extra flooring should I buy?
Home Depot recommends 5 to 10% extra for cuts and mistakes. Use the high end for rooms with many corners, closets or angled walls, and more again for diagonal or herringbone patterns. Check the installation guide for your product, since some brands state their own number.
How many boxes of laminate do I need for 500 square feet?
With 10% extra you need 550 sq ft. Divide by the square feet printed on the box: 28 boxes at 20 sq ft per box, or 23 boxes at 24 sq ft per box.
Do I need underlayment?
Most laminate and many vinyl plank floors need an underlayment unless one is already attached to the planks. Hardwood uses its own felt or membrane. Follow the flooring maker's instructions, since the wrong underlayment can void the warranty.
Should I measure closets and hallways separately?
Yes. Measure each space as a rectangle, add the areas, and enter the total with "I know the square feet". The square footage calculator adds several areas for you.