Blog · Floors & Walls
How to Estimate Flooring Materials
Measure the floor, pick a waste allowance that matches your layout, round up to whole boxes, then add the trim and underlayment that go with it.
Step 1: Measure the floor area
Measure each room in feet and multiply length × width. Split L-shaped rooms into rectangles, and include closets and alcoves that get the same floor. For example, a 12 × 15 ft bedroom (180 ft²) with a 3 × 5 ft closet (15 ft²) has 195 ft² to cover. The square footage calculator adds several rectangles for you.
Step 2: Choose a waste allowance for your layout
Every cut at a wall, doorway or corner leaves an offcut, and more complex layouts leave more. Common planning allowances are around 10% for a straight lay in a simple room, about 15% for diagonal layouts or rooms with many jogs, and 15–20% or more for herringbone and chevron. Check the manufacturer’s or installer’s advice for your product.
Step 3: Round up to whole boxes
Divide the area including waste by the coverage printed on one box, then round up. Using the 195 ft² example and a box that covers 22.5 ft²:
| Layout | Allowance | Area to buy | Boxes at 22.5 ft² |
|---|---|---|---|
| Straight lay | 10% | 214.5 ft² | 10 |
| Diagonal | 15% | 224.3 ft² | 10 |
| Herringbone | 20% | 234 ft² | 11 |
Box coverage varies a lot between products, so enter your own figure in the flooring calculator. Buy every box from the same batch or lot so the colour matches, and keep a spare box for future repairs if you can.
Step 4: Tile floors need setting materials too
For tile, the tile calculator counts tiles and boxes, then the thinset calculator and grout calculator estimate the bags that go with them. If the subfloor needs flattening first, the self-leveling concrete calculator works out the compound for your average depth.
Step 5: Trim and underlayment
- Baseboard: the room’s perimeter minus door openings. The bedroom above is 2 × (12 + 15) = 54 ft around before the closet and doors. The baseboard calculator turns that into whole lengths.
- Underlayment: usually sold by area, so start from the floor area without the cutting waste and check the roll or pack coverage.
- Transitions: count each doorway where the new floor meets a different one.
Common mistakes
- Adding waste twice: once in the measurements and again as a percentage.
- Using the box’s piece count instead of its printed coverage in square feet.
- Forgetting closets, or the floor under appliances that will be moved.