Tile Calculator · Practical guide
How Many 12x12 Tiles Do I Need for 100 Square Feet?
The math on a 100 sq ft floor with 12x12 tiles, grout gaps, and wastage built in.
At a glance
The Short Answer
A 12x12-inch tile covers exactly one square foot, so 100 square feet needs about 100 tiles before waste. With a standard 1/8-inch grout gap and a 10% wastage allowance for cuts and breakage, plan on 110 tiles.
Interactive tool
Tile Calculator
Enter your own values, then compare the result with the examples below.
Tile Estimate
How the Count Is Calculated
Take a 10 ft x 10 ft room (120 inches per side). Adding the 0.125-inch grout gap makes each tile's effective size 12.125 inches, so 120 / 12.125 = 9.9, which rounds up to 10 tiles per row, 10 rows, 100 tiles total. Adding 10% wastage gives 110 tiles to buy.
| Wastage Allowance | Tiles to Buy | Best For |
|---|---|---|
| 0% (bare minimum) | 100 | Perfect rectangles, no cuts |
| 10% (standard) | 110 | Straight lay in simple rooms |
| 15% (patterned) | 115 | Diagonal or herringbone layouts |
Buying by the Box
Tiles are usually sold by the box. If your tile comes 10 per box, 110 tiles means 11 boxes. At 15 per box, you need 8 boxes — that leaves a few spares, which is a good thing: keep them for future repairs, since tile lines get discontinued.
Non-Square Areas
"100 square feet" says nothing about shape. A 5 ft x 20 ft hallway is also 100 sq ft but fits tiles differently along each dimension — 60 inches / 12.125 rounds to 5 tiles, and 240 / 12.125 rounds to 20, still 100 tiles before waste. Enter your exact width and length above rather than relying on square footage alone.
Frequently Asked Questions
Does one 12x12 tile really cover one square foot?
Yes — 12 inches by 12 inches is exactly 144 square inches, or one square foot. The grout gap slightly increases coverage per tile, but the calculator rounds up per row, so the count stays the same for most rooms.
What grout gap should I use for 12x12 floor tiles?
1/8 inch (0.125") is the most common choice for standard floor tile. Rectified tiles with precise edges can go as narrow as 1/16 inch, while rustic tiles may need 3/16 inch or more.
How many boxes of 12x12 tile do I need for 100 sq ft?
It depends on tiles per box: 110 tiles (including 10% waste) is 11 boxes at 10 per box, or 8 boxes at 15 per box. Enter your box size in the calculator to get the exact count.
Should I round up or buy exactly 100?
Always round up. Cuts at walls and around obstacles consume partial tiles, breakage happens, and matching dye lots later is difficult. A 10-15% buffer is standard practice.