How much flooring do I need?
Multiply the room's length by its width to get square feet, add any closets or nooks, and subtract anything the floor won't go under, like a kitchen island. Then add an allowance for cuts and round up to whole boxes, because flooring is sold by the box.
Example: a 14' x 11' 6" bedroom is 161 sq ft. With 10% extra you need about 177 sq ft. If a box covers 23.6 sq ft, that's 7.5 boxes — so you buy 8.
How much extra to order
| Layout | Suggested extra | Why |
|---|---|---|
| Straight, random stagger | 10% | The cut-off end of one row usually starts the next. |
| Diagonal (45°) | 15% | Every piece along a wall is an angled cut. |
| Herringbone | 20% | Short planks and a cut at every edge. |
Add a little more for rooms with many corners, closets or doorways, and keep one unopened box. If a plank gets damaged years from now, you'll have a perfect color match.
Why the first and last rows matter
The room's width almost never divides evenly by the plank width. Whatever is left over becomes the last row along the far wall. If that leftover is tiny — say half an inch — the strip is nearly impossible to click in and looks like a mistake. Most install guides want the last row at least 2" wide.
The fix is to rip the first row too, so both edge rows come out the same width. With "Balance first & last rows" on, the planner does this math for you and shows the exact width to cut.
Stagger, end pieces and the "H" joint
End joints in neighboring rows need to be offset — commonly at least 6 to 8 inches — so the floor stays locked together and doesn't show a ladder or "H" pattern. Pieces at the end of a row also have a minimum length, often 8 inches. The planner simulates the install row by row, starting each row with the leftover from the last one when it fits the rules, and flags anything that breaks them. You can change both rules to match your product's guide.
Expansion gap, trim and transitions
Floating floors move with temperature and humidity, so they need a gap at every wall — usually 1/4" for vinyl plank and a bit more for laminate and engineered wood. Very long rooms may need a bigger gap or a transition strip partway; your product's guide gives the limit. The gap is hidden by baseboard or quarter round. The planner estimates quarter round from the room's perimeter minus doorways, in 8-foot pieces with 10% extra, and adds one transition strip for each doorway.
Which way should the planks run?
Most rooms look best with planks running along the longest wall or toward the main window. In hallways, run them lengthwise. Use the direction switch to compare: changing direction changes your row widths and sometimes the amount of cutting.
Planning a tiled bathroom or kitchen instead? Try the tile calculator & layout planner.