How does the tile calculator work?
The calculator divides the area you are tiling by the area of one tile, then adds a waste factor for cuts and breakage. The formula is tiles = area ÷ tile area × (1 + waste%). A 100 sq ft floor with 12 × 12 in tiles (1 sq ft each) needs 100 tiles, and a standard 10% waste brings it to 110 tiles. Enter a room size or a total square footage, pick the tile size, and it rounds up to whole tiles — and whole boxes if you add the tiles-per-box count.
How much extra tile should I buy?
Add 10% for a straight or grid layout, about 15% for a diagonal (45°) layout, and 20% for herringbone, chevron, or other patterns. Patterns cut more tiles at an angle, and the triangular offcuts usually cannot be reused. Bump it up another 5% for an irregular room or if it is your first install. The extra also leaves you a few spare tiles from the same batch for future repairs — dye lots change between batches.
Why round up to whole tiles and boxes?
You cannot buy a fraction of a tile, and tile is sold by the box. So the calculator rounds the tile count up, then rounds the box count up too. If you enter 6 tiles per box and need 110 tiles, that is 19 boxes (114 tiles). Buying full boxes from one dye lot is the safe move — running short mid-job often means a new batch that no longer matches.
How to figure out tile by hand
- 1
Measure the area in square feet. Multiply the room length by the width in feet. A 10 ft × 10 ft floor is 100 square feet. Measure walls the same way (width × height).
- 2
Find the area of one tile. Multiply the tile width by its length in inches, then divide by 144. A 12 × 12 in tile covers 1 sq ft; a 12 × 24 in tile covers 2 sq ft.
- 3
Divide the area by the tile size. That is the bare tile count. 100 sq ft ÷ 1 sq ft per tile = 100 tiles, before any waste.
- 4
Add 10–20% for waste and round up. Multiply by 1.10 for a straight layout (110 tiles), more for diagonal or herringbone. Always round up to whole tiles — and whole boxes.
Tile reference charts
Quick-reference tables for sizing a tile order.
Tiles needed per 100 sq ft by tile size
How many tiles cover 100 square feet, including a 10% waste factor for a straight layout. Scale it: for 250 sq ft, multiply by 2.5.
| Tile size | Each covers | Tiles per 100 sq ft |
|---|---|---|
| 12 × 12 in | 1.00 sq ft | 110 tiles |
| 12 × 24 in | 2.00 sq ft | 55 tiles |
| 6 × 24 in (plank) | 1.00 sq ft | 110 tiles |
| 18 × 18 in | 2.25 sq ft | 49 tiles |
| 3 × 6 in (subway) | 0.13 sq ft | 880 tiles |
| 4 × 4 in | 0.11 sq ft | 990 tiles |
Source: Socko calculation: 100 sq ft ÷ tile area × 1.10, rounded up to whole tiles.
How much extra tile to order (waste factor)
The waste factor covers edge cuts, breakage, and a few spares from the same dye lot. Add it to your measured area before ordering. Use the higher end for an irregular room or a first install.
| Layout | Add for waste |
|---|---|
| Straight / grid lay | 10% |
| Brick / offset (subway) | 10% |
| Diagonal (45°) | 15% |
| Herringbone or chevron | 20% |
| Any layout, irregular room or first install | +5% more |
Tiles needed by room size (12 × 12 in tile)
For the most common floor tile (12 × 12 in, 1 sq ft each), with a 10% waste factor. For 12 × 24 in tile, use about half as many.
| Room size | Floor area | Tiles (12 × 12) |
|---|---|---|
| 5 × 8 ft | 40 sq ft | 44 tiles |
| 8 × 10 ft | 80 sq ft | 88 tiles |
| 10 × 10 ft | 100 sq ft | 110 tiles |
| 10 × 12 ft | 120 sq ft | 132 tiles |
| 12 × 12 ft | 144 sq ft | 159 tiles |
| 12 × 15 ft | 180 sq ft | 198 tiles |
| 15 × 20 ft | 300 sq ft | 330 tiles |
Source: Socko calculation: floor area ÷ 1 sq ft × 1.10, rounded up to whole tiles.
Frequently asked questions
How many 12×12 tiles do I need for 100 square feet?
A 12 × 12 in tile covers exactly 1 sq ft, so 100 sq ft needs 100 tiles bare — about 110 tiles with a standard 10% waste factor.
How do I calculate how many tiles I need?
Divide the area by one tile's area, then add waste: tiles = area ÷ tile area × (1 + waste%). A tile's area is width × length ÷ 144 (square feet). Round up to whole tiles.
How much extra tile should I order for waste?
About 10% for a straight layout, 15% for diagonal, and 20% for herringbone or patterns. Add ~5% for an irregular room or a first-time install.
How many tiles do I need for a 10x10 room?
A 10 × 10 ft room is 100 sq ft: about 110 of the 12 × 12 in tiles, or about 55 of the larger 12 × 24 in tiles, with 10% waste.
Do I include doors, niches, or cutouts in the area?
Measure the full rectangle and let the waste factor absorb small openings. Subtract only large fixtures (a tub footprint, an island) that remove real area.
How do I figure out how many boxes of tile to buy?
Divide tiles needed by tiles per box and round up: 110 ÷ 6 = 19 boxes. Buy whole boxes from one dye lot so the color matches.
Does tile size change how many tiles I need?
Yes — bigger tiles mean fewer pieces for the same area. A 12 × 24 in tile covers twice a 12 × 12, so you need half as many. The square footage and waste % are unchanged.
Is the tile calculator free, and is my data saved?
Yes — it is free and runs entirely in your browser. Nothing you type is sent or stored.
This tool is for estimation and education, not financial advice. See our methodology for how these figures are calculated and sourced.