How Much Tile for a Bathroom?

Updated 2026-07-19

Few things stall a bathroom remodel faster than running out of tile with two rows left to set. Because tile is fired in lots, the same style bought a month later can come back a shade off, and in a small bathroom that mismatch reads from the doorway. The fix is boring but bulletproof: measure carefully once, add a sensible waste factor, and buy everything in a single trip.

The math itself is nothing more than length times width, applied to the floor and then to each wall you plan to cover. Where people go wrong is not the multiplication — it is forgetting a wall, skipping the waste factor, or trusting the square footage on boxes pulled from mixed lots. Here is the process a tile setter would walk through on an estimate.

Step 1: Measure the floor

Start with the footprint. Multiply the room length by its width in feet. A classic hall bath is 5 × 8 feet, which is 40 square feet of floor. Measure wall to wall, even behind where the vanity will sit — most pros tile the entire floor before the vanity and toilet go in, so the finish looks built-in rather than patched around cabinets.

1. Measure at floor level, not at countertop height — walls are rarely perfectly plumb.
2. For L-shaped bathrooms, split the floor into rectangles, calculate each one, and add them together.
3. Ignore the toilet flange and register cutouts; the few inches you would save get eaten by cuts anyway.

Step 2: Measure the tub or shower walls

Wet walls are where the square footage hides. For a standard 60-inch alcove tub tiled 6 feet up the wall, you are covering three surfaces: the 5-foot back wall (5 × 6 = 30 sq ft) and two 30-inch side walls (2.5 × 6 = 15 sq ft each). That is 60 square feet — more than the entire floor of a small bath.

For a walk-in shower, measure each wall separately: width times finished tile height. Tile usually stops at 6 feet or runs to the ceiling, so confirm the height before you multiply. Count the shower floor and any niche interiors on their own lines, since those often take a different, smaller tile than the walls.

Step 3: Add the right waste factor

Industry standard is 10% extra for a straight (grid) layout and 15% for diagonal, herringbone, or any pattern that generates heavy cuts at the walls. Small bathrooms honestly deserve the high end of that range: in a 5 × 8 room, nearly every tile touches a wall, a flange, or a door jamb, so cut waste is proportionally higher than in a big open kitchen.

Multiply your measured total by 1.10 or 1.15, then round up to full boxes. When the job is done, keep one unopened box in the attic — a cracked tile five years from now is a 20-minute repair if the spare matches the original dye lot.

Worked example: a 5 × 8 hall bath

Floor: 5 × 8 = 40 sq ft. Tub surround: 60 sq ft. Total = 100 sq ft. With a straight lay at 10% waste, you need 110 sq ft; run the same room on a diagonal and the target climbs to 115.

Say you picked a 12 × 24 porcelain sold 8 pieces to a box, 16 sq ft per box. At 110 sq ft you need 6.9 boxes — so you buy 7. That one rounding decision is the difference between grouting on Sunday and driving back across town hoping the shelf lot matches what you already set.

Mistakes that leave you short

Once your floor and wall totals are on paper, drop them into the tile calculator to confirm the box count and waste allowance before you load the cart.

1. Buying for the floor and forgetting the walls until the thinset is already mixed.
2. Subtracting the vanity and toilet areas, then deciding mid-job to tile the whole floor anyway.
3. Using 5% waste because it looked like enough — budget 10% minimum, 15% for diagonal layouts.
4. Mixing boxes from different dye lots; check the lot number printed on every box before checkout.
5. Rounding down to a neat box count. Round up, always.