How Much Extra Tile Do You Need for Herringbone?

Short version: there's no single number. We had a look at 34 real herringbone floors people planned in Herron, and the waste ran from about 6% in big, simple rooms to over 20% in small, fiddly ones, with the middle of the pack sitting around 12%. So the "just add 10%" advice you'll read everywhere is fine for a big living room, but it quietly leaves you short on a small bathroom. Which camp you're in comes down mostly to one thing: how big your room is, and how many walls it has to cut around.

That extra tile isn't a sign you've done anything wrong. It's baked into the pattern. Below is the real picture from those rooms, why small rooms get hit hardest, two floors counted tile by tile, and how to land on your own number instead of a rule of thumb.

The Real Numbers, by Room Size

Most guides hand you one figure and move on. "Herringbone wastes about 15%, buy 15% extra." It's a guess in a nice outfit. Here's what actually happened across those 34 real floors, grouped by room size:

The median came out around 12%, and most rooms landed between 7% and 17%.

Fair warning: 34 rooms is a real sample, not a huge one, so treat the small-room figures as a strong steer rather than gospel. Your exact number depends on your room's shape and your tile size, which is the bit the planner works out for you.

Why Small Rooms Waste So Much More

Here's the why. Once it clicks, the whole table makes sense.

In herringbone, every tile that meets a wall gets cut at a 45 degree angle. Those angled offcuts are little triangles, and they almost never fit anywhere else, so they head for the bin. A straight lay is kinder here, because the offcut from one row often starts the next. That means nearly all of herringbone's waste lives at the edges of the room, in the band of cut tiles running around your walls.

Now the sneaky part, and it's pure geometry. A room's walls grow with its width, but its floor grows with the square of its width. Make a room twice as big and you get four times the floor but only twice the wall. So in a big room, that wasteful edge band is a thin frame around a lot of floor. In a small room, the same band is most of the floor. That's the whole reason a 2m by 3m bathroom can hit 20% while a 6m by 5m living room sits near 6%. Same pattern, same tile, completely different bill.

Two things make it worse. An awkward shape (an L, an alcove, a chimney breast) adds more edge per square metre. And a big tile in a small room means fewer tiles overall, so every cut costs you a bigger share of the total. (If you're also weighing up chevron, the waste picture is even more different than you'd expect.)

Two Real Rooms, Counted Piece by Piece

Ranges are handy, but the honest way to answer "how much extra?" is to lay a real room out and count the pieces. Here are two, run through Herron's tiling engine, straight lay first and then herringbone, so you can see exactly what the pattern costs.

Example 1: a regular 4.0m × 3.0m room, 600×300mm porcelain

A 12.0 m² room (about 129 sq ft), 600×300mm porcelain, 3mm grout joint, 10mm expansion gap.

Same room, same tile, and herringbone means 7 more tiles laid and 8 more to buy.

Example 2: an L-shaped room, 1200×180mm plank

An L-shaped room, 5.0m × 3.6m with a 2.0m × 1.6m return (14.8 m², about 159 sq ft), laid in a 1200×180mm plank, 3mm joint, 10mm gap.

The L-shape pushes herringbone waste from about 16% in the regular room to nearly 20%. Every extra corner is another run of triangular offcuts.

Why the Standard 10% Leaves You Short

Here's something that jumped out of the real projects. Almost everyone leaves the waste allowance on the default 10% and never touches it. For a big, simple floor that's grand, you'll finish with a bit spare. But on a small or cut-up room, where the real waste is 15% to 22%, a 10% buffer means you run out halfway through. Then you're back at the shop ordering another box, probably from a different batch, with a slightly different shade. Not fun on a floor you'll look at every day.

For herringbone, a safer place to start:

• Big, simple, rectangular room: 10% to 12%.
• Medium room, or a few corners and cuts: around 15%.
• Small room (under about 8 m²) or an awkward shape: 18% to 20%.

These are still rules of thumb, mind. The only way to actually know is to lay the floor out.

How to Keep Herringbone Waste Down

You can't change the geometry, but you can work with it. A few things genuinely help.

Centre the pattern on the room's focal point

Where you start laying matters a lot. If the zigzag lines up with the room's visual centre (the fireplace, the main doorway, the middle of a hallway), the cuts on both sides tend to come out more balanced. Balanced cuts mean bigger perimeter triangles on average, and bigger triangles waste less, with some even reusable. It's almost impossible to judge on the floor, but in a layout you just drag the starting point and watch the edge cuts change. Shifting by half a tile can make a real difference.

Check how your tile size fits the room

A 75×300mm tile makes a different cut pattern than a 100×400mm tile in the same room. Sometimes a slightly different size turns lots of small, wasteful triangles into fewer, larger, tidier cuts. If you're torn between two tiles you like equally, let the layout decide.

Look for offcut pairs

In some layouts, the triangle you cut off one edge tile is the exact mirror of one you need further along the same wall. Spot those pairs and one tile gives you two usable pieces instead of one piece and a scrap. Herron's herringbone layout tool finds these automatically and counts the reuse into the total (7 reused pieces in the regular room above, 15 in the L-shape). Doing it by hand is possible, just tedious. A cut list groups the pieces by size so you can batch the identical ones from the same stock tile.

The Bottom Line

Herringbone is worth every bit of the extra tile it asks for. A well-laid herringbone floor changes a room in a way no straight lay ever will. But "worth it" and "wing it" are different things.

The extra waste isn't random. It comes from specific, predictable places: the diagonal edge cuts, the ramp-up rows, and the fragments around obstacles. Know where it hides and you can plan for it. Plan for it and you can keep it down. And if you lay your room out in the herringbone layout tool before you order, you can walk in confident you've bought enough to finish without spending hundreds more than you need to.

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