Quick lookup
Tiles needed for common projects (10% waste included)
Counts assume 12×12 in (1 sq ft each) tiles for floors and 4×4 in (0.111 sq ft) tiles for backsplash. Adjust if your tile is a different size. Thinset + grout estimates included.
| Project | Sq ft | + 10% waste | 12×12 tiles | Thinset bags | Grout bags |
|---|---|---|---|---|---|
| 5 × 8 ft bathroom floor | 40 | 44 | 44 | 1 | 1 |
| 8 × 10 ft bathroom floor | 80 | 88 | 88 | 1 | 1 |
| 10 × 10 ft kitchen floor | 100 | 110 | 110 | 2 | 1 |
| 12 × 14 ft floor | 168 | 185 | 185 | 3 | 2 |
| 3 × 8 ft (24 sq ft) backsplash | 24 | 26 | 234 (4×4) | 1 qt mastic | 1 |
| Shower walls (60 sq ft) | 60 | 66 | 66 | 1 | 1 |
| 10 × 12 ft entryway | 120 | 132 | 132 | 2 | 2 |
| Subway tile bathroom (80 sq ft walls) | 80 | 88 | 88 (subway) | 1 | 1 |
Order 15% extra for diagonal layouts, herringbone, or your first tile job. Wall tile usually allows mastic (cheaper); floor tile needs thinset mortar.
Quick answer
How many tiles do I need?
Tile count: area × waste factor ÷ tile area, rounded up. The most common mistakes: skipping the waste factor (always 10%, 15% for diagonal), using the wrong tile area (a "12 inch" tile is usually 11.6 inches actual size, not 12.0), and forgetting grout — every tile job needs it.
Our tile calculator handles standard sizes (4×4, 6×6, 8×8, 12×12, 12×24, 18×18, 24×24) plus custom, calculates grout bag needs based on joint width, and gives you total project cost.
The math
The formula explained
Tile count
Convert tile dimensions to feet: tileArea = (W in inches × H in inches) / 144. For a 12 × 12 tile that's 144 / 144 = 1 sq ft. For an 8 × 8 tile it's 64 / 144 = 0.44 sq ft.
Then tiles = ⌈areaWithWaste / tileArea⌉.
Waste factor
Straight installation (grid): 10%. Diagonal: 15%. Herringbone or pinwheel: 15-20%. Round rooms with lots of cuts: 20%.
Grout coverage
Depends on tile size and joint width. 1/8 inch joints with 12×12 tile: a 25 lb bag covers ~175 sq ft. 1/4 inch joints (for natural stone): same bag covers ~80 sq ft.
What to use where
Tile size guide
Small tiles (4 inch and under)
Mosaic backsplashes, shower niches, decorative borders. More grout lines means more grip but also more sealing maintenance.
Standard tiles (6×6 to 12×12)
Bathrooms, kitchens, entryways. The 12×12 is the most popular floor size in the US.
Large format (12×24, 24×24)
Open floor plans. Looks modern, makes rooms feel bigger. Needs a perfectly flat substrate — lippage between tiles is much more visible at this size.
Plank tiles (6×36, 8×48)
Wood-look or stone-look. Install with 1/3 offset (not 1/2) to minimize lippage at the staggered seams.
Use cases
Common projects
Standard bathroom floor (8' × 6')
48 sq ft + 10% = 53 sq ft. 53 × 12 " tiles.
Master bathroom (10' × 12')
120 sq ft + 10% = 132 sq ft. 132 tiles.
Kitchen floor (12' × 15')
180 sq ft + 10% = 198 sq ft. 198 × 12" tiles.
Kitchen backsplash (15 ft × 18")
22.5 sq ft + 10% = 25 sq ft. 100 × 6" tiles or 25 × 12".
Shower walls (3 walls × 7' tall)
Depends on stall — typically 60-90 sq ft + 15% (more cuts).
Entryway (6' × 8')
48 sq ft + 10% = 53 sq ft. 14 × 24" tiles for modern look.
From a tile setter
Pro tips
- Buy from one dye lot. Different lots can have visible color shifts even within the same product code.
- Dry-lay before tile setting — arrange tiles without thinset to see if you'll have skinny cuts at the edges. Adjust your starting line if so.
- Use 1/4 inch backer board (HardieBacker or Durock) under tile, never just plywood. Tile cracks over flexible substrates.
- Mix 2-3 boxes at a time during installation to blend any subtle color variations.
- Grout sealer is mandatory for natural stone and recommended for any porous grout. Reapply yearly.
- Keep 1 extra box for repairs. Tile lines are discontinued constantly.
The 10% rule is the floor, not ceiling
Related calculators
Tile work usually means demo, prep, and finishing — these calculators cover the whole bathroom or kitchen reno.
Flooring Calculator
Vinyl, laminate, or hardwood for adjacent rooms
Drywall Calculator
Cement board or drywall under tile
Paint Calculator
Walls above the tile line
Concrete Calculator
Self-leveling underlayment volume
Mortgage Calculator
Financing a kitchen or bath remodel
Roofing Calculator
Roof tile counts for clay or slate roofs
Last reviewed: · Methodology based on US building code standards, contractor pricing surveys, and manufacturer specifications.