Tile Calculator
Higher for diagonal layouts, large tiles, or oddly shaped rooms.
Printed on the box.
Boxes to buy (incl. 10% waste)
14 boxes
- Tiles needed
- 132
- Tiles per box at this size
- 10
- Spare tiles left over
- 8
- Floor area
- 120 ft² (132 ft² with waste)
Material cost
$630.00
- Per box
- $45.00 for 10 ft²
- Cost per square foot installed area
- $5.25
Same floor, other tile sizes
| Tile size | Tiles | Boxes |
|---|---|---|
| 12" × 12" (standard floor tile) | 132 | 14 |
| 12" × 24" (large format) | 66 | 14 |
| 18" × 18" | 59 | 15 |
| 24" × 24" (polished concrete look) | 33 | 17 |
| 6" × 6" (small / mosaic-friendly) | 528 | 14 |
| 3" × 6" (subway) | 1,056 | 14 |
Tile count is geometric — it ignores grout lines, cuts around fixtures, and pattern repeats, so always keep the leftover boxes until the job is done. Product sold by area rather than by piece? Use the flooring calculator instead. Prices here are placeholders — swap in your store's.
A 10 × 12 ft floor takes 132 tiles of 12 × 12 in tile with a 10% waste allowance — 120 ft² of floor plus 12 ft² for cuts and breakage. Tile is sold by the box, not the piece, so that's 14 boxes at 10 ft² per box, which leaves 8 spare tiles for future repairs. Change the tile size, the box coverage, or the waste allowance and the count, the boxes, and the spares all re-run together.
How many tiles do I need?
Four steps, and the third is the one people skip:
floor area (ft²) = length (ft) × width (ft)
area + waste (ft²) = floor area × (1 + waste%)
tile area (ft²) = (tile width in ÷ 12) × (tile length in ÷ 12)
tiles needed = area with waste ÷ tile area, rounded up
boxes = tiles ÷ tiles per box, rounded up
Worked example — the page default, a 10 × 12 ft room with 12" × 12" tile:
- Floor: 10 × 12 = 120 ft²
- Add 10% waste: 132 ft²
- A 12" × 12" tile is exactly 1 ft² → 132 tiles
- At 10 ft² per box (10 tiles), that's 14 boxes — 140 tiles, so 8 spares
Why the box count is the number you actually buy
Tile shops don't split boxes, and dye lots don't match across batches — so the order is always whole boxes, and the leftovers are yours to keep. That has two practical consequences:
- The box count can stay flat while the tile count moves. On the default floor, raising waste from 10% to 15% takes the tile count from 132 to 138, but the box count stays at 14 — you just lose spares (8 → 2).
- Spares are not waste. Those 8 leftover tiles are what you'll use in three years when one cracks and the style is discontinued. If the calculator says 0 spares, add a box.
Same floor, different rooms
| Room | Floor size | Tiles (12" × 12") | Boxes | Spares | Cost at $45/box |
|---|---|---|---|---|---|
| Bathroom | 8 × 5 ft | 44 | 5 | 6 | $225 |
| Bedroom (default) | 10 × 12 ft | 132 | 14 | 8 | $630 |
| Kitchen + entry | 15 × 12 ft | 198 | 20 | 2 | $900 |
| Open-plan living | 20 × 15 ft | 330 | 33 | 0 | $1,485 |
All rows use the page's defaults — 12" × 12" tile, 10 ft² per box, 10% waste, $45 per box as a placeholder price. The 20 × 15 ft room lands on 0 spares; that's the row where you add a box on purpose.
The three inputs people get wrong
- Waste percentage. 10% covers straight-lay cuts in a rectangular room. Go to 15% for a diagonal (45°) layout or a room with lots of inside corners, and 20% for large-format tile in an irregular space with a pattern. Bigger tile means fewer pieces but more waste per broken piece.
- Tile size in inches, not feet. Tile is sold in inches; the math needs feet. A 12" × 24" tile is 2 ft² — half the piece count of the default floor (66 tiles, 9 boxes at 16 ft² per box) — while a 6" × 6" tile is 0.25 ft² and needs 528 pieces for the same floor.
- Box coverage. Cartons are labeled in square feet, not pieces: 10 ft² per box holds 10 tiles at 12" × 12", but only 8 at 12" × 24". Read the carton and change the field.
How to use this calculator
- Enter the floor length and width in feet — measure wall to wall, not around the cabinets.
- Pick the tile size (or type custom dimensions in inches).
- Set the waste allowance; 10% is the default.
- Check the box coverage and price per box against the carton in front of you.
- Read the tile count, the boxes to buy, and the spares you'll have left.
Frequently asked questions
How many tiles do I need for 120 square feet?
132 with a 10% waste allowance, assuming 12" × 12" tile (1 ft² each) — 120 tiles exactly, plus 12 for cuts. That's 14 boxes at 10 ft² per box.
How much waste should I add for tile?
10% for a straightforward rectangular room with a straight lay. Move to 15% for diagonal layouts or rooms with many corners, and 20% for large-format tile, patterns, or irregular shapes.
Why does it say 14 boxes when I only need 132 tiles?
Because tile is sold by the box — 10 ft² per box here, so 10 tiles per box. Fourteen boxes is 140 tiles, and the 8 extras are your spares for repairs and cutting mistakes.
How many tiles come in a box?
It depends on the tile, which is why the calculator asks for coverage per box in square feet instead of a piece count. At 10 ft² per box: 10 tiles of 12" × 12", 8 of 12" × 24", 40 of 6" × 6". Check your carton.
Should I order extra tile for breakage?
Yes — that's what the waste allowance is for, and the spares line tells you what's left after buying whole boxes. If spares come out at 0, buy one more box; replacements later often won't match the dye lot.
Does thinset or grout change how much tile I need?
No. Adhesive and grout are separate material orders and don't change the tile count. What changes the count is layout: diagonal patterns and large-format tile both raise the waste percentage.
Data sources: Every figure here is arithmetic from the dimensions you enter — floor area, the inch-to-foot tile conversion, and whole-box rounding. The 10% default waste allowance is the common estimating practice for straight-lay tile; 15–20% for diagonal and large-format layouts is standard trade guidance, not a rule. The $45-per-box price is a placeholder, not a market quote — replace it with your carton's price. This is a materials estimating tool; for wet areas, movement joints, and substrate requirements, follow the tile manufacturer's installation instructions and your local code. Related tools: flooring calculator, paint calculator, concrete calculator, all home project calculators, mm to inches.