Wall and backsplash tile calculator

Add each wall you are tiling, take off the windows and doors, and get the net area, tiles and boxes. Heights can be typed in inches, like 18″, even while widths are in feet.

To buy

167 tiles

including 10% waste. Add tiles per box to get a box count.

Walls 22.5 sq ft (2.09 m²), less 3.00 sq ft (0.279 m²) of openings, leaves 19.5 sq ft (1.81 m²) to tile. With the joint, each tile covers 0.13 sq ft (0.012 m²): 151.2 tiles before waste, 167 after.

Area breakdown

Surface	Size	Area
Wall 1	12 ft (3.66 m) × 1 ft 6 in (0.46 m)	+ 18.0 sq ft (1.67 m²)
Wall 2	3 ft (0.91 m) × 1 ft 6 in (0.46 m)	+ 4.50 sq ft (0.418 m²)
Opening 1	3 ft (0.91 m) × 1 ft (0.30 m)	− 3.00 sq ft (0.279 m²)
Net area to tile		19.5 sq ft (1.81 m²)

By pattern

The same net area at each pattern's usual waste allowance. Subway tile is normally laid offset; herringbone backsplashes are popular and cost noticeably more tile.

Pattern	Waste	Tiles	Boxes
Straight (grid)	10%	167	—
Offset (brick, 1/3 or 1/2)	10%	167	—
Diagonal (45°)	15%	174	—
Herringbone or chevron	20%	182	—

How to use it

Treat every flat surface you are tiling as a wall: the back of a backsplash, each return, each side of a shower, the face of a tub apron. Measure the width along the wall and the height you will tile, not the height of the room. For a backsplash that is usually countertop to cabinet underside; for a shower it is the top of the tub or tray to wherever the tile stops.

Then list anything inside those rectangles that will not be tiled and is large enough to save whole tiles: a window, a door, the hood above a range, a pass-through. Use the count box when you have several identical openings. Leave outlets and switches in; the tile around them is still bought and cut.

The method

Gross area = the sum of width × height for each wall.
Openings = the sum of width × height × count for each opening.
Net area = gross − openings.
Tiles = net area ÷ ((tile length + joint) × (tile width + joint)) × (1 + waste %), rounded up; boxes = tiles ÷ tiles per box, rounded up.

The joint matters more on walls than floors, because wall tiles tend to be small. A 3 × 6 in subway tile with a 1/16 in joint covers 3.0625 × 6.0625 in, about 3% more than its face, so ignoring the joint over-orders by about 3%.

A worked example

The default is an L-shaped backsplash: 12 ft and 3 ft of wall, both 18 in high. That is 18 + 4.5 = 22.5 sq ft. A window dips 12 in into the backsplash over a 3 ft width, taking off 3 sq ft and leaving 19.5 sq ft (1.81 m²). Each 3 × 6 in subway tile with its joint covers 18.57 square inches, so the wall takes 151.2 tiles exactly and 167 with 10% waste. No box size is entered, so the answer is a tile count; type the number of tiles per box to turn it into boxes.

Heights and common wall-tile sizes

Kitchen backsplash: usually 18 in (450 mm) from counter to wall cabinets in US kitchens; more behind a range.
Tub surround: commonly tiled to about 5 to 6 ft (1.5 to 1.8 m) above the tub rim, or to the ceiling.
Walk-in shower: often floor to ceiling, which makes a single wall 8 ft (2.4 m) or more high.
Wainscot: a half-height band, usually 36 to 48 in (0.9 to 1.2 m).

These are conventions, not rules; measure what you have. Subway tile is sold in 3 × 6, 3 × 12, 4 × 12 and 2 × 8 in formats, among others, and box counts vary by maker, so read the carton.

Where this stops being reliable

Sloped ceilings and gable walls. A wall under a stair or roof slope is a trapezoid. Split it into a rectangle and a triangle and work out the area with the area calculator, then enter it here as one wall of equivalent size.
Busy walls. A backsplash with a window, three outlets, a corner and an end panel can easily use 15% or more for cuts. Raise the waste figure.
Mosaic sheets. Mosaics are sold by the sheet. Enter the sheet's dimensions as the tile size with a zero joint (the joints are built into the sheet), and the count is sheets.
Decorative bands and trims. Listellos, pencil liners and bullnose are sold by the piece or the length and are not included.

To decide where the first course and the first vertical joint go, use the tile layout calculator; to buy grout, the grout calculator.

Common questions

Should I subtract small openings like outlets and switches?

No. An electrical box is cut out of a tile that you still have to buy, so subtracting it would under-order. Subtract only openings big enough that whole tiles are saved: windows, doors, a range hood that comes down to the counter, a niche you are finishing in a different material.

How high should a kitchen backsplash be?

The common standard in US kitchens is 18 in (about 450 mm) between the countertop and the underside of the wall cabinets, and the backsplash usually fills that gap. Behind a range without cabinets above, many people take the tile up to the hood or the ceiling. Measure your actual gap; older kitchens and European units differ.

How do I measure a shower surround?

Enter each wall separately: back wall width by tiled height, and each end wall the same way. Enter the tub or shower-tray side as an opening only if the wall measurement included it. If the walls include a niche, add its back and sides as another small wall; its opening does not reduce the tile needed, because the niche is tiled inside.

Why is the waste allowance the same on a wall as on a floor?

The cutting is similar: a wall has edges at the ceiling or cabinet line, both corners and every opening, just as a floor has walls and door frames. Walls with many openings and short runs, like a backsplash broken up by windows and outlets, often need more than 10%, and 15% is a safer figure there.

What about trim, bullnose or edge profiles?

They are ordered by length, not area. Measure every exposed edge that needs finishing (the top of a backsplash that stops below the cabinets, the outside edge of a shower wall) and add 10% for mitres and cuts. This calculator does not count them.