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Tile Calculator - How Many Tiles Do You Need

Free tile calculator for floors and walls. Enter room and tile dimensions to find how many tiles you need, plus a worked example and waste-allowance guide.

Tile Calculator

Enter Measurements

Area Dimensions

m
m

Tile Dimensions

m
m

Results

Tiles Needed
48
Total Area
12.00m²
Tile Area
0.25m²

Visualization

4 × 3 m
Total Area: 12.00 m²
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Showing first 20 tiles

How It's Calculated

The number of tiles needed is calculated by dividing the total area by the area of a single tile, then rounding up to the nearest whole number (since you can't use a partial tile).

Tiles Needed = Ceiling( (Area Length × Area Width) ÷ (Tile Length × Tile Width) )
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Documentation

What Is a Tile Calculator?

A tile calculator finds the number of tiles needed to cover a floor, wall, or other flat surface. It divides the total area to be covered by the area of one tile, then rounds up, since a partial tile cannot be bought or laid.

Tile size varies a lot between products, so a room's square footage alone does not say how many tiles are needed. A 12 square meter bathroom needs a different tile count with 30 cm tiles than it does with 60 cm tiles. The calculator removes that guesswork.

How to Calculate Tiles Needed

The formula has two steps: find the area to cover, find the area of one tile, then divide and round up.

Tiles Needed=⌈Area Length×Area WidthTile Length×Tile Width⌉\text{Tiles Needed} = \left\lceil \frac{\text{Area Length} \times \text{Area Width}}{\text{Tile Length} \times \text{Tile Width}} \right\rceil

  • Area Length and Area Width are the dimensions of the surface, measured in meters.
  • Tile Length and Tile Width are the dimensions of one tile, in meters.
  • The symbol ⌈ ⌉ means "round up to the nearest whole number" (the ceiling function).

Rounding up matters because a fraction of a tile cannot be installed. If the division gives 15.2 tiles, the true requirement is 16 whole tiles.

This formula assumes tiles are laid edge to edge, with no gap. Real installations leave a grout line between tiles, usually 2 to 10 millimeters wide. For most rooms this gap changes the tile count by very little. For very small tiles or wide grout lines, add the grout width to each tile dimension before calculating.

Formula in Code

1import math
2
3def tiles_needed(area_length, area_width, tile_length, tile_width):
4    area = area_length * area_width
5    tile_area = tile_length * tile_width
6    return math.ceil(area / tile_area)
7
8# 4m x 3m room, 0.3m x 0.3m tiles
9print(tiles_needed(4, 3, 0.3, 0.3))  # 134
10

Worked Example

Consider a bathroom floor that measures 4 meters by 3 meters, tiled with 30 cm by 30 cm (0.3 m by 0.3 m) porcelain tiles.

  1. Total floor area: 4 m × 3 m = 12 m²
  2. Area of one tile: 0.3 m × 0.3 m = 0.09 m²
  3. Divide: 12 ÷ 0.09 = 133.33
  4. Round up: 134 tiles minimum

This figure covers the floor with no spares. Installers commonly add extra tiles to cover breakage, mistakes, and future repairs. Adding 10% to 134 tiles gives 134 × 1.10 = 147.4, rounded up to 148 tiles.

Fixtures such as a toilet or vanity do not usually get subtracted from the area. Cutting tiles around a fixed object often wastes as much material as the space it removes, and the extra tiles are useful later if a tile cracks.

How Much Extra to Buy

The calculator returns the minimum number of tiles for full coverage with no waste allowance. Trade practice adds a percentage on top, depending on the layout:

  • Simple rectangular rooms (a bathroom or laundry room): add about 10%.
  • Rooms with corners, alcoves, or multiple walls: add 15% to 20%, since more cuts mean more breakage.
  • Diagonal, herringbone, or other angled patterns: add 20% to 25%, because edge tiles need angled cuts that often fail on the first try.

The Tile Council of North America notes that even professional installers commonly budget 10% to 15% waste into commercial jobs. It also helps to keep 5 to 10 spare tiles after a project finishes, since tile color lots change and an exact match may not be available years later.

How to Use This Calculator

  1. Measure the length and width of the surface in meters, wall to wall.
  2. Check the tile packaging for its actual size, which can differ slightly from the marketed size. A tile sold as "30×30 cm" may measure 29.8 × 29.8 cm.
  3. Enter both sets of measurements. The calculator shows the total area, the area of one tile, and the number of tiles needed.

For measurements taken in feet or inches, convert to meters first: 1 foot equals 0.3048 meters, and 1 inch equals 0.0254 meters.

This tool works for any flat surface, not only floors. For a wall, enter the wall's length and height instead of a floor's length and width. For an L-shaped room, split it into two rectangles, calculate each separately, and add the two tile counts together.

Frequently Asked Questions

How many tiles do I need for a 10×10 meter room?

A 10 m × 10 m room covers 100 m². With 30 cm × 30 cm tiles (0.09 m² each), the minimum is 100 ÷ 0.09 = 1,111.1, rounded up to 1,112 tiles. Adding 10% for waste (about 112 tiles) brings the total to roughly 1,224 tiles. Note that a "10×10" room measured in feet, not meters, covers only about 9.3 m², a much smaller area.

How accurate is a tile calculator?

The arithmetic is exact: area divided by tile area, rounded up. Accuracy in practice depends on how carefully the room and tile were measured, and on adding enough extra for waste. A calculator cannot account for out-of-square corners, patterned layouts, or a builder's skill with a tile cutter, which is why the waste percentage matters.

How do I work out tiles per square meter?

Divide 1 by the tile's area. For a 30 cm × 30 cm tile (0.09 m²), that is 1 ÷ 0.09 ≈ 11.1 tiles per square meter. A 12 m² bathroom would then need about 12 × 11.1 = 133.3, rounded up to 134 tiles minimum, before any waste allowance.

Does the calculator include grout lines?

No. It assumes tiles sit edge to edge. Grout lines, typically 2 to 10 mm wide, add a small amount of extra area that is usually covered by the waste allowance. For very small tiles or wide grout, add the grout width to each tile dimension before calculating.

How many extra tiles should I buy?

About 10% for a simple rectangular room, 15% to 20% for a room with several corners or obstacles, and 20% to 25% for diagonal or patterned layouts. Keep 5 to 10 spare tiles after the job for future repairs.

Can this calculator be used for wall tiles or an L-shaped room?

Yes. For a wall, use its length and height in place of a floor's length and width. For an L-shaped room, split the space into two rectangles, calculate tiles for each one, and add the totals together.

What is the difference between nominal and actual tile size?

The nominal size is the rounded name used for marketing, such as "12×12 tile." The actual size is the precise measurement printed on the box, which is often slightly smaller to allow for a grout joint. Calculations should always use the actual size, since the small difference adds up over a large project.

References

  1. Tile Council of North America. TCNA Handbook for Ceramic, Glass, and Stone Tile Installation.
  2. National Institute of Standards and Technology. Guide to SI Units.
  3. International Organization for Standardization. ISO 10545: Ceramic Tiles Standards.