Tile Calculator
Enter floor area and tile size to get the exact tile count, the order quantity with pattern waste included, and the thinset and grout the job consumes.
Last updated: 2026-09-28
How the calculation works
- The exact count divides area by the tile's face area; the buy count adds pattern waste and rounds up.
- Diagonal layouts cut more edge tiles from each piece, hence the higher 15% waste.
- Thinset (~1 lb per 5 ft²) and grout (~1 lb per 8 ft² at 1/8 in joints) are working averages for standard layouts.
Formula
tile area = (size in)² ÷ 144 ft² tiles = area ÷ tile area × (1 + waste)
| Symbol | Meaning | Unit |
|---|---|---|
A | Area to tile | ft² |
waste | Cut waste by pattern: 10% straight, 15% diagonal | — |
Worked example
Interpreting the result
Order everything at once: dye lots vary between production batches, and matching an out-of-stock lot months later is often impossible. Check the actual tile dimensions (nominal sizes shrink after firing) and keep a few spare tiles from the job for future repairs — the 10% waste usually leaves them. Large-format tiles change the labor: flatter substrates, back-buttering and leveling systems become mandatory rather than optional.
Assumptions
- Square tiles; rectangular layouts need the actual face area per tile.
- 10% waste straight lay, 15% diagonal — moderate room shape complexity.
- Thinset and grout averages for standard 1/4-3/8 in trowels and 1/8 in joints.
Limitations
- Mosaic sheets, herringbone and brick-joint patterns have different waste (herringbone can exceed 20%).
- Heated floors, membranes and crack isolation add layers not counted here.
Frequently asked questions
How many 12×12 tiles do I need for 100 square feet?
100 tiles exactly, plus 10% waste → 110; buy 11 boxes if they're packed 10 per box. Diagonal layout: 115 tiles.
How much waste should I add for tile?
10% for straight layouts in simple rooms, 15% diagonal, 15-20% for herringbone or rooms with many corners and jogs. Keep the leftovers — future matching depends on them.