12×18 ft living room with 18×18 in tile: 18 boxes, $952.50
For a 12×18 ft living room (12 × 18 ft, 9 ft walls) covered in 18×18 in tile using the “Standard grid (10% allowance)” layout pattern, RoomTakeoff's quantity method computes 18 tile boxes for a grid of 8 columns by 12 rows (96 cells), 3 gallons of wall paint, 63 linear ft of trim, and an entered-price material total of $952.50, as of 2026-09-11 (RoomTakeoff, method 1.0.0).
- Floor area
- 216 sq ft
- Tile boxes
- 18
- Wall paint
- 3 gal
- Trim
- 63 linear ft
- Grout
- 1 bag
- Material total
- $952.50
| Stage | Material | Quantity | Estimated cost | Dependency |
|---|---|---|---|---|
| 1 · Verify | Substrate / waterproofing | Not calculated | Not included | Confirm substrate, flatness, moisture, and installation system |
| 2 · Order | Tile | 18 boxes | $648.00 | Confirm lot, orientation, transitions, and actual box contents |
| 3 · Order | Grout | 1 bag | $12.00 | Generic coverage formula; confirm with your grout product |
| 4 · Finish | Wall paint | 3 gallons | $135.00 | Surface preparation and manufacturer coverage |
| 5 · Fit | Trim | 63 linear ft | $157.50 | Finished floor elevation and opening measurements |
How the 18 boxes are worked out
The grid needs 96 whole tiles (8 × 12, each partial edge cell counted as a full tile). Adding the 10 percent allowance gives 106 tiles, and at 6 tiles per box that rounds up to 18 boxes, or 108 tiles with 12 beyond the bare grid. Walls: 540 sq ft gross minus 50 sq ft of openings leaves 490 sq ft, which at 2 coats needs 3 gallons. Trim: 60 ft of perimeter minus a 3 ft door, plus the allowance, is 63 ft.
Waste by layout in this room
| Layout pattern | Tiles ordered | Boxes |
|---|---|---|
| Standard grid (10% allowance) | 106 | 18 |
| Straight lay, clean cuts (5% allowance) | 101 | 17 |
| Brick or diagonal offset (15% allowance) | 111 | 19 |
| Herringbone or complex (20% allowance) | 116 | 20 |
A diagonal or offset lay (15 percent planning allowance) needs 19 boxes here against 17 boxes for a straight lay with clean cuts (5 percent), a difference of 2 boxes. The drawing and grid count always assume a straight grid; only the allowance changes.
Assumptions behind this number
This worked example uses a 9 ft ceiling, 50 sq ft of wall openings, a 3 ft door/opening deduction from trim, a 0.125 in grout joint, 6 tiles per box, 2 paint coats at 350 sq ft per gallon coverage, and the Standard grid (10% allowance) tile/trim allowance. Every tile cell, including a partial edge cell, consumes one whole tile: there is no offcut reuse, movement-gap, or irregular-room modeling. Change any of these assumptions in the live planner below to match your actual room, tile, and prices; this page is a starting estimate, not a purchase order. Waste percentages (5, 10, 15 and 20 percent), 350 sq ft per gallon paint coverage, 2 coats and a 1/8 in grout joint are RoomTakeoff planning assumptions, not figures taken from a manufacturer or standards document. Check the label on your tile, paint and trim, and confirm installation practice with the tile manufacturer or the Tile Council of North America resources linked below.
Reference sources
Other tile sizes in this room
- 12×12 in tile: 17 boxes, $916.50
- 12×24 in tile: 15 boxes, $844.50