Flooring Calculator
Updated 2026-10-12
Enter the room size and how much one box covers. The calculator adds a waste allowance, rounds up to whole boxes, and can estimate the cost.
How the flooring calculator works
Flooring is sold by the box, and each box states how much floor it covers. The calculator finds the room's area, adds a percentage for waste, divides by the coverage of one box, and rounds up, because you can't buy part of a box.
Worked example
A 15 × 12 ft living room is 180 sq ft. Adding 10% waste brings it to 198 sq ft. If each box of laminate covers 20 sq ft, you need 9.9 boxes, so buy 10. At $45 a box, that's $450 for the flooring itself.
How much waste to allow
Every row of planks ends with a cut piece, and you'll also cut around doorframes, closets and heating vents. For a plain rectangular room with planks running parallel to the longest wall, 5–7% is often enough. Most rooms land around 10%. Diagonal layouts and rooms with lots of corners, alcoves or angled walls can need 15% or more. Herringbone and chevron patterns typically need 15–20%.
Measuring tips
- Measure wall to wall. Measure at the widest points, including the space under radiators or doors where flooring will go.
- Split odd shapes. For an L-shaped room, measure it as two rectangles and add the areas.
- Include closets. If the flooring continues into a closet or hallway, add those areas too.
- Don't subtract built-ins unless they're permanent. Kitchen islands and fitted cabinets can be subtracted; furniture can't.
Other things to buy
Floating floors such as laminate and many vinyl planks often need an underlayment, sold in rolls by area, so use the same area figure. You'll also want transition strips at doorways and new baseboard or quarter-round trim to cover the expansion gap around the edges. Check the manufacturer's instructions: some vinyl planks have underlayment already attached.
Waste allowance by layout
| Layout | Suggested waste |
|---|---|
| Straight planks in a simple rectangular room | 5–7% |
| Typical room with doorways and a closet | 10% |
| Diagonal layout, or many corners and angles | 15% |
| Herringbone or chevron | 15–20% |
If you are new to installing flooring, lean towards the higher figure. Mistakes on the first few rows are common, and an extra box is cheaper than a second trip to the store for a product that may have sold out.
Expansion gaps and transitions
Laminate, engineered wood and most floating vinyl floors expand and shrink slightly with humidity and temperature. Manufacturers ask for a small gap around the edges of the room and around fixed objects such as pipes and door frames. The gap is hidden by baseboard or quarter-round trim. The exact width varies by product, so follow the installation guide in the box. Large rooms may also need an expansion joint across a doorway, covered by a transition strip. These details don't change the number of boxes you need, but plan for the trim and strips in your budget.
Estimating the total cost
Enter the price per box to see the cost of the flooring itself, and what that works out to per square foot or square meter of your room. Remember that the per-area price on the shelf tag is for the flooring only. Underlayment, trim, transition strips, adhesive (for glue-down floors) and any removal of the old floor all add to the total.
Frequently asked questions
- How many boxes of flooring do I need for 500 sq ft?
- With 10% waste you need 550 sq ft. At 20 sq ft per box, that's 28 boxes (27.5 rounded up).
- Should I keep leftover boxes?
- Yes. Keep at least one spare box. If a plank gets damaged later, the same product or color may no longer be available.
- Do I need to let flooring acclimate?
- Many laminate and hardwood products recommend leaving the boxes in the room for 24–72 hours before installing. Follow the instructions printed on your boxes.