How to use the backsplash calculator
- Add a row for each wall section: the main runs between counter and cabinets, beside the fridge, and the taller area behind the range.
- Subtract any windows. Leave outlets and switches in — you tile around them and the offcuts are waste anyway.
- Choose the tile and the grout joint, and set the extra for cuts.
- Optionally enter the coverage per box and the price.
The formula
Area = Σ (section length × height) − windows Tile + joint = (tile width + grout) × (tile height + grout) Tiles = Area × (1 + extra %) ÷ (tile + joint) → round up Boxes = Area × (1 + extra %) ÷ coverage per box → round up
Worked example
A 10 ft run of counter with an 18 in backsplash, tiled in 3 × 6 in subway tile with 1/16 in grout and 10% extra:
- Area = 10 × 1.5 = 15 ft² (2,160 in²)
- Each tile plus grout covers 3.0625 × 6.0625 = 18.57 in²
- Tiles = 2,160 × 1.1 ÷ 18.57 = 128 tiles
Tiles per square foot
| Tile | Tiles per ft² (no grout) | Tiles per m² |
|---|---|---|
| 2 × 12 in | 6 | 65 |
| 3 × 6 in subway | 8 | 86 |
| 4 × 4 in | 9 | 97 |
| 4 × 8 in | 4.5 | 48 |
| 4 × 16 in | 2.25 | 24 |
| 6 × 6 in | 4 | 43 |
| 12 × 12 in mosaic sheet | 1 | 10.8 |
Grout joints slightly reduce the number of tiles needed; the calculator includes them.
Planning tips
- Standard height: in most US kitchens the gap between countertop and upper cabinets is 18 inches; behind a range it is often 24–30 inches to the hood.
- Lay out before you stick: dry-fit a row to centre the pattern on the sink or range and avoid thin slivers at the ends.
- Outlets: turn off the power, remove cover plates and use box extenders so outlets sit flush with the new tile.
- Pattern waste: herringbone, chevron and diagonal layouts need 15–20% extra.
- Grout colour changes the look: matching grout gives a seamless finish, contrasting grout highlights the pattern.
- Seal natural stone and cement tiles before grouting to prevent staining.
Edges and trim
Where the backsplash stops at an open wall or the side of a cabinet, the cut edge of the tile shows. Finish it with bullnose tiles, a pencil liner or a metal or PVC edge profile. The calculator gives an upper estimate of edge length; measure the edges that will really be exposed before buying trim.
Metric example
A 3 m run of worktop with a 45 cm high splashback is 1.35 m². Using 75 × 150 mm metro tiles with 2 mm joints, each tile plus joint covers about 0.0118 m², so 1.35 × 1.1 ÷ 0.0118 gives roughly 127 tiles including 10% extra. If the tiles come in boxes covering 0.5 m², you would buy three boxes. Always check that every box comes from the same batch or dye lot so the colour matches across the wall.