Tile Calculator
Calculate how many tiles you need for a floor or wall — with grout gap, waste factor and boxes-to-buy included. Presets for common tile sizes from mosaic to large format.
Printed on the tile box label
You might also need:Paint Calculator·Drywall Calculator
How tile quantities are calculated
tiles = (area ÷ per-tile coverage) × waste factor, rounded up
Including the grout gap in each tile's footprint is the accurate way to count — with small mosaic tiles and wide joints it changes the total by several percent. For a 10 × 8 ft floor in 12×12 tile with ⅛-inch joints, you need 79 tiles before waste; order 87 at 10%.
Tiles per 100 sq ft (⅛″ joints, before waste)
| Tile size | Tiles per 100 sq ft |
|---|---|
| 4 × 4″ | ~847 |
| 3 × 6″ subway | ~753 |
| 6 × 6″ | ~383 |
| 12 × 12″ | ~98 |
| 12 × 24″ | ~49 |
| 24 × 24″ | ~25 |
Ordering tips
- Same dye lot: check the batch numbers on every box match — color shifts between lots are visible on a floor.
- Layout from the center: dry-lay a row both directions from the room's center line so cut tiles at the walls end up even on both sides.
- Wall tile counts the same way: use wall height × width as your area. Tiling over new drywall or backer board? Count sheets with the drywall calculator first.
Frequently asked questions
How much extra tile should I buy?+
Buy 10% extra for straight layouts, 15% for diagonal or herringbone patterns, and up to 20% for rooms with many cuts or large-format tile. Also keep a few spares after the job — dye lots change, and a matching replacement later may be impossible.
How many 12x12 tiles do I need per square foot?+
One — a 12×12 inch tile covers exactly 1 square foot. A 100 sq ft floor needs 100 tiles plus waste, so order about 110.
How do I account for grout lines?+
Grout gaps slightly reduce the number of tiles needed, since each tile effectively covers its own size plus the gap. The effect is small (2–4%) and is normally ignored in ordering — the waste factor absorbs it. This calculator includes the grout gap in its per-tile coverage for accuracy.
How many tiles come in a box?+
It varies by size and brand, but boxes typically cover 10–15 square feet: 12×12 tiles often come 10–12 per box; 12×24 come 8; large 24×24 porcelain may be 3–4 per box. Enter your box coverage to get a box count.
What size trowel and how much adhesive do I need?+
For tiles up to 12 inches use a ¼ × ¼ inch square-notch trowel — a 50 lb bag of thinset covers 75–85 sq ft. Large-format tiles need a ½-inch notch and back-buttering, dropping coverage to 40–50 sq ft per bag.