How Much Hardwood Flooring Do I Need?

Hardwood needs more waste than laminate

A 16 × 12 room is 192 sq ft. At 20 sq ft per box with a 10% allowance: 11 boxes.

At 15%: 12.

Three reasons the allowance runs higher than for laminate:

Random lengths. Solid hardwood usually arrives in mixed lengths rather than uniform planks, so you can't plan cuts precisely — you take what the box gives you.

Natural variation. Knots, colour that doesn't match, damaged edges. Some boards get set aside, and that's normal rather than a supplier problem.

Offcuts are less reusable than they look. The end of one row can only start the next if it's long enough to meet the minimum stagger.

10% covers a simple rectangle. 15% is sensible for diagonal or herringbone layouts, or a room with many angles.

Acclimation is where hardwood floors actually fail

Not the fitting. Not the subfloor. This.

Wood moves with humidity. Boards delivered from a cold lorry or a dry warehouse into a heated house will change dimension over the following days.

If they're already nailed down when that happens, the floor gaps in winter or buckles in summer.

The standard practice: bring the boxes into the room where the floor will be laid, open or cross-stack them, and leave them for several days before starting. Follow the manufacturer's stated time, not a general figure.

Almost every catastrophic hardwood failure traces back to someone in a hurry skipping this step.

Leave the expansion gap

Around half an inch, around the entire perimeter, covered by skirting or beading.

It exists so the floor can move seasonally — which it will whether you allow for it or not.

Laying tight to the wall is the other classic way to make a floor buckle, and it's completely invisible until the first humid summer. At which point the fix is lifting the floor.

The calculator shows the perimeter (56 ft for our room) for exactly this reason.

Order it all at once, and keep what's left

Wood colour and grain vary between production runs. A later box will not match.

Order the whole job in one batch and record the lot number.

And keep the leftovers — 28 sq ft spare on our example. A plank you can slot in after a plumbing leak or a damaged board is worth far more than the few pounds it cost, and matching one two years later is close to impossible.

Read the box coverage off the label

It varies substantially between products, and it's the number the whole count divides by.

Two floors that look similar in a showroom can have very different coverage per box — so a box count from one product tells you nothing about another.

Worth checking what you actually end up with, too: whole boxes always overshoot. 11 boxes at 20 sq ft is 220 sq ft for a 192 sq ft room.

Which way to run the boards

Not a quantity question, but it's decided before you order and it's awkward to change later.

The usual conventions: along the longest wall, which makes a room read longer and means fewer end joints; or toward the main light source, so the joints between boards are less visible. In a narrow hallway, running the length is almost always right.

The one that overrides both: on a suspended timber floor, boards normally run perpendicular to the joists so each board spans several of them. That's structural, and it's the same principle as sheathing a subfloor — work out the aesthetic answer, then check whether the structure permits it.

What this doesn't count

All separate order lines, and all easy to forget until the day:

• Underlay — for floating floors, sold by the roll
• Adhesive or nails, depending on the fixing method
• Thresholds at every doorway, and at any change of flooring
• Beading or new skirting to cover the expansion gap

That last one catches people. If you're keeping existing skirting, you need beading; if you're replacing it, the skirting has to come off before the floor goes down and back on after.

Rooms that aren't rectangles

Measure as several rectangles and add the areas. Don't use the bounding box of an L-shape — it includes floor you're not covering.

And note that a complicated shape is itself a reason to move to the higher waste allowance. More corners means more cuts, and more cuts means more offcuts too short to start a row.

Print the order and fitting sheet — it has a field for the lot number and a checklist where acclimation sits above anything to do with tools.