Tile Calculator
Calculate how many tiles you need for floors, walls and backsplashes — including waste and grout spacing.
Last updated: September 2026 · Reviewed for floor, wall and backsplash tile estimating
How to Use This Tile Calculator
- Enter the length and width of the area you want to tile
- Enter the size of one tile
- Add grout gap (usually 1/8" or 3 mm)
- Choose waste factor (10% for straight lay, 15%+ for diagonal)
- Optionally enter tiles per box and price for cost estimate
- Click Calculate Tiles to see total tiles, boxes and cost
Common Tile Examples (12×12" Tile, 1/8" Grout, 10% Waste)
Quick reference for popular room sizes. Re-calculate with your exact tile size and waste.
| Room Size | Room Area | Tiles Needed |
|---|---|---|
| 5 × 8 ft (bath) | 40 ft² | ~44 tiles |
| 10 × 12 ft | 120 ft² | ~130 tiles |
| 12 × 15 ft | 180 ft² | ~195 tiles |
| 15 × 20 ft | 300 ft² | ~325 tiles |
Figures are approximate. Always use your product’s tile size and buy from the same lot for color match.
Recommended Waste Factor
| Layout | Waste % |
|---|---|
| Straight lay (simple room) | 5 – 10% |
| Straight lay with many cuts | 10 – 12% |
| Diagonal pattern | 15 – 20% |
| Herringbone / complex pattern | 15 – 25% |
Common Tile Sizes
| Tile Size | Common Use |
|---|---|
| 12" × 12" | Floors, bathrooms |
| 12" × 24" | Modern floors & walls |
| 6" × 6" / 4" × 4" | Backsplash, showers |
| 3" × 6" subway | Kitchen backsplash |
| 18" × 18" / 24" × 24" | Large format floors |
Formulas Used
Room Area = Length × Width
Tile Area (with grout) = (Tile Length + Grout) × (Tile Width + Grout)
Tiles Needed = (Room Area ÷ Tile Area) × (1 + Waste%)
Always round up to the next whole tile. Boxes are also rounded up.
How Many Tiles Do I Need?
Ordering the right number of tiles avoids extra trips to the store and leftover boxes. This calculator accounts for tile size, grout joints and waste so you get a realistic count.
Floors
Measure the full floor area. For L-shaped rooms, split into rectangles and add the results. Large-format tiles (18×18 or bigger) often need less waste percentage than small tiles.
Walls & Backsplashes
Measure only the area that will be tiled. Subtract windows, doors or cabinets if they are not tiled. Backsplashes are usually measured as height × length of the wall section.
Grout Matters
Even a 1/8" joint adds up across a large floor. Including the grout gap in the calculation gives a more accurate tile count, especially with smaller tiles.
Tips for Ordering Tile
- Buy extra — keep 5–10% for future repairs; dye lots change.
- Check the box label — tiles per box and coverage vary by manufacturer.
- Order from the same lot when possible to avoid shade variation.
- Diagonal layouts need more waste — plan on 15% or higher.
- Acclimate tiles — let them sit in the room before installation.
Frequently Asked Questions
Related measurements
Room area cross-check: square footage calculator. Other floor finishes: flooring calculator. After tiling, walls: paint calculator. Browse all construction calculators.