How this calculator works
This runs our flooring and baseboard calculators on one room. Boxes are the area plus waste divided by the coverage of a box, rounded up. Underlayment comes in rolls of 100 ft², and the baseboard follows the perimeter of the room less the doorways.
Worked example: a 15 × 12 ft room (180 ft²) with 10% waste and 20 ft² boxes takes 10 boxes, 2 rolls of underlayment, 7 boards of 8 ft baseboard with two 3 ft doorways, and 2 transition strips.
Boxes by room size (20 ft² boxes, 10% waste)
With 100 ft² underlayment rolls, and 8 ft baseboard for two 3 ft doorways.
| Room | Boxes | Underlayment rolls | Baseboard boards |
|---|---|---|---|
| 10 × 12 ft | 7 | 2 | 6 |
| 12 × 12 ft | 8 | 2 | 6 |
| 12 × 15 ft | 10 | 2 | 7 |
| 12 × 18 ft | 12 | 3 | 8 |
| 16 × 20 ft | 18 | 4 | 10 |
Tips before you buy
- Pick the direction before you start. Planks usually run along the longest wall, or toward the main light. Check the width of the last row: a sliver looks bad and can lift.
- Measure doors and appliances. The new floor is thicker, so a dishwasher or a door may need clearance.
- Leave an expansion gap around the walls; the baseboard or quarter round covers it.
- Buy from one batch. Dye lots vary, and a later box may not match.
- Undercut door casings with a jamb saw so that the planks slide beneath them.
Tools & materials for this project
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Frequently asked questions
How many boxes of laminate do I need for a 12x15 room?
10 boxes of 20 ft² for the 180 ft² room with 10% for cuts. With a simple straight layout and 5% waste it is 10.
Do I need underlayment for laminate or vinyl plank?
Usually, unless the planks have a pad attached. This room takes 2 rolls of 100 ft². Concrete floors also need a vapor barrier: check what the maker requires.
How much baseboard do I need?
7 boards of 8 ft, for the perimeter less two 3 ft doorways, plus 10%. Quarter round on the old baseboard hides the expansion gap.
How much extra flooring should I buy?
5% for a simple straight room, 10% for diagonals or many cuts, and 15% for herringbone or patterns, plus an extra box for later repairs.
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Related calculators & guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.