Quick answer:Measure each wall’s height × width, add the walls together, subtract doors and windows, divide by one tile’s square footage, and add 10% waste (15% for diagonal or herringbone). A 120 sq ft net wall area in 12×12 tile needs about 132 tiles, or 14 boxes of 10.
Wall tile follows the same formula as any other tile project — area divided by tile size, plus a waste allowance. The two things that make walls different are that you measure height by width for each wall, and you almost always subtract openingslike doors and windows. Here’s the full method, or skip straight to the tile calculator for an instant count.
How to measure a wall for tile
- Measure the width and height of each wall you plan to tile, in feet.
- Multiply width × height to get each wall’s area, then add all walls together.
- Measure every door, window, and permanent fixture opening the same way.
- Subtract those openings from the wall total to get your net tile area.
Wall 2: 6 ft × 8 ft = 48 sq ft
Less door: 3 ft × 7 ft = −21 sq ft
Less window: 3 ft × 1 ft = −3 sq ft
Net wall area: 120 sq ft
Choosing a wall tile size
- 3×6 subway — classic, 0.125 sq ft each
- 4×4 square — traditional bath/kitchen, 0.111 sq ft each
- 12×12 — large-format wall panels, 1 sq ft each
- 12×24 — modern, fewer grout lines, 2 sq ft each
Larger tiles mean fewer grout lines and a faster install, but they need a flat wall and create more cutting waste around openings. Mosaic sheets are sold by the square foot rather than by individual tile.
Worked example: 120 sq ft, 12×12 tile
Base tiles: 120 ÷ 1 = 120
+ 10% waste (12 tiles): 132 tiles
Boxes of 10: 132 ÷ 10 = 13.2 → 14 boxes
Layout pattern and waste
Your layout drives how much extra tile to buy. A straight or stacked wall layout needs about 10% waste, while herringbone, diagonal, and chevron patterns need around 15% because of the extra angled cuts at every edge and opening. See how much extra tile you should buy for a full breakdown by pattern.
Tips for buying wall tile
- Order every tile from the same dye lot so colors match.
- Measure each wall separately — walls are rarely the same size.
- Don’t forget to subtract large openings; they add up fast.
- Keep a few spare tiles for future chips and repairs.
Frequently asked questions
- How do I calculate how much wall tile I need?
- Measure each wall's height and width in feet and multiply them for that wall's area. Add every wall together, subtract doors, windows, and other openings, then divide the net area by one tile's square footage. Add 10% waste (15% for diagonal or herringbone) and round up.
- Do I subtract windows and doors when calculating wall tile?
- Yes. Measure each opening's height and width, multiply for its area, and subtract it from the wall total. Skipping this step makes you over-buy — a single 3 ft × 5 ft window is 15 sq ft, which can be a full box of large-format tile.
- How much extra wall tile should I buy?
- Add about 10% for a straight or stacked layout and 15% for herringbone, diagonal, or chevron patterns, which need more angled cuts. Buy whole boxes and keep the spares for future repairs.
- Is calculating wall tile different from floor tile?
- The math is identical — area divided by tile size, plus waste. The only difference is that you measure height × width for each wall instead of length × width for a floor, and you almost always subtract door and window openings.
Enter each wall and opening into the tile calculator — it adds multiple surfaces, subtracts openings, and counts by tile or by box. For specific wall projects, see how to calculate shower tile and how to calculate backsplash tile, or start with how many tiles do I need.
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