How Many Subway Tiles for a Kitchen Backsplash? (3×6 Guide)
Quick answer: a 3×6 subway tile covers 18 sq in (0.125 sq ft), so you need about 8 tiles per square foot. A 20 sq ft backsplash plus 10% waste needs roughly 176 tiles. Here's the measurement and the per-foot math.
Step 1: measure the backsplash
The backsplash runs from countertop to cabinet, usually about 18 in tall, across the wall width. Measure the height and width in inches, multiply, and divide by 144 to get square feet. If the tile wraps around a corner, do each wall separately and add them. A 10 ft wall at 18 in high is 120 × 18 = 2,160 sq in = 15 sq ft.
Step 2: the 3×6 math
A 3×6 subway tile is 18 sq in. There are 144 sq in in a square foot, so 144 ÷ 18 = 8 tiles per square foot. Multiply your backsplash area by 8, then add 10% waste (15% for herringbone or diagonal). Worked example — 15 sq ft backsplash:
- 15 × 8 = 120 tiles
- Add 10% = 12 → buy ~132 tiles
Backsplash size → tile count
At 8 tiles per sq ft plus 10% waste:
| Backsplash area | Full tiles | +10% waste |
|---|---|---|
| 10 sq ft | 80 | 88 |
| 15 sq ft | 120 | 132 |
| 20 sq ft | 160 | 176 |
| 30 sq ft | 240 | 264 |
Outlets, corners and waste
You cut tiles around outlets, corners and at the end of every row, so even though outlets take area away, you still use most of those tiles. Most installers keep the 10% waste rather than subtracting the small outlet area. It's safer to buy a couple of extra full tiles than to drive back for a second trip mid-install.
Common mistakes
- Using inches where you meant feet. Keep everything in inches, then ÷144 for sq ft.
- Forgetting to wrap corners. Count each wall face separately.
- No waste on a diagonal pattern. Herringbone uses 15%, not 10%.
- Buying by the box without checking the count. Subway tile boxes vary — verify the tiles per box on the label.