How to use the flooring calculator
- Add each area to be floored. Split L-shaped or irregular rooms into rectangles.
- Choose your layout pattern — it sets the waste allowance.
- Add an additional extra for awkward rooms, lots of doorways or spare planks.
- Enter the coverage per box from the label, and optionally the price per box and underlayment roll size.
The formula
Floor area = Σ (Length × Width) Flooring needed = Floor area × (1 + Waste %) Boxes = Flooring needed ÷ Coverage per box → round up Underlayment = Floor area × 1.05 ÷ Roll coverage → round up
Worked example
A 15 × 12 ft living room and a 10 × 10 ft hall in vinyl plank, straight lay, 20 ft² per box:
- Floor area = 180 + 100 = 280 ft²
- With 10% waste = 308 ft²
- Boxes = 308 ÷ 20 = 15.4 → 16 boxes (320 ft²)
- In a herringbone pattern with 20% waste: 336 ft² → 17 boxes
Waste factors by layout
| Layout | Waste allowance | Notes |
|---|---|---|
| Straight / random stagger | 7–10% | Cut-offs can start the next row |
| Diagonal (45°) | 15% | Angled cuts at every wall |
| Herringbone / chevron | 15–20%+ | Many short pieces and end cuts |
| Small or broken-up rooms | add 5% | Closets, hallways, bathrooms |
| Natural hardwood with grade variation | add 5% | Culling boards for colour or defects |
Measuring tips
- Measure wall to wall at the longest and widest points, ignoring baseboards.
- Include closets and the space under appliances such as the dishwasher only if flooring will go there.
- Doorways: measure to the middle of the threshold, where a transition strip will sit.
- Stairs are usually priced separately with stair nosing.
- Round up each measurement to the next inch.
Before you install
- Check the subfloor: most floating floors need it flat within about 3/16 in over 10 ft.
- Acclimate the boxes in the room for the time the manufacturer specifies.
- Mix boxes: open several boxes and mix planks for a natural colour spread.
- Leave an expansion gap (often ¼–⅜ in) at every wall for floating floors, hidden by baseboard or quarter-round.
- Plan the first row so the last row isn’t a thin sliver — adjust the starting width if needed.
Costs to remember
Besides the flooring itself, budget for underlayment, transition strips, quarter-round or new baseboards, adhesive or nails for glue-down and nail-down floors, removal and disposal of the old floor, and installation labour if you are not doing it yourself.
Choosing a flooring type
Luxury vinyl plank is waterproof and a popular choice for kitchens, bathrooms and basements. Laminate is scratch-resistant and affordable but most products don’t tolerate standing water. Engineered hardwood has a real wood top layer over a stable core and can usually be installed over concrete; solid hardwood can be sanded and refinished many times but needs a wood subfloor and stable humidity. Whatever you choose, buy everything at once from the same lot so colour and texture match.