TILE CALCULATOR

Tile Calculator — How Many Tiles Do I Need?

Calculate how many tiles you need for a floor, wall, backsplash or any tiled surface. Choose from common tile sizes or enter custom dimensions, set your grout joint width and waste allowance, and get an instant tile count with an estimated grout quantity.

Area to tile

Tile size

Grout gap & waste

Tiles needed
—tiles

Enter area and tile size to calculate.

Get an Accurate Tile Count for Any Floor, Wall or Backsplash

The Interior Tailor Tile Calculator tells you how many tiles to buy for a floor, wall, backsplash or any other tiled surface. Enter the length and width of the area, pick a common tile size or type your own, set the grout gap and waste allowance, and get an instant tile count with an estimated grout quantity. Because the calculator counts each tile together with its grout joint, you get a more realistic number than a simple square footage guess, and the waste setting helps you cover cuts, breakage and pattern layouts.

What the Tile Calculator Includes

  • Floors, walls and backsplashes: enter any rectangular area in feet or metres.
  • Common tile sizes: 4x4, 6x6, 12x12, 12x24, 18x18 and 24x24 inch presets, plus a custom size.
  • Grout gap presets: 1/16, 1/8, 3/16 and 1/4 inch, or enter your own.
  • Adjustable waste percentage: add extra for diagonal and herringbone layouts.
  • Built-in grout estimate: see roughly how much grout the job needs alongside your tile count.

How Tile Count Is Calculated

Each tile occupies its face area plus half a grout joint on all sides. The effective area per tile is:

Tile Area = (Tile W + Gap) × (Tile H + Gap)

Tiles = Total Area ÷ Tile Area × (1 + Waste %)

A 10% waste allowance is standard for straight layouts. Increase to 15% for diagonal installations and up to 20% for complex patterns such as herringbone, which generate more offcuts at the edges.

Tile Size & Grout Joint Guide

  • Small tiles (≤6 in): 1/16–1/8 in grout joint — mosaic, penny round, subway
  • Medium tiles (6–12 in): 1/8–3/16 in joint — standard floor and wall tile
  • Large tiles (12–24 in): 3/16–1/4 in joint — large format floor tile
  • Large format (24 in+): 1/4–3/8 in joint — rectified porcelain slabs

Rectified tiles (precision-cut to exact dimensions) allow tighter joints of 1/16 in or less. Non-rectified tiles need wider joints to hide size variations.

Choosing the Right Tile for Each Area

  • Floors: Use tiles rated for floor use (PEI 3+). Larger formats make small rooms look bigger.
  • Wet areas (showers, tub surrounds): Glazed porcelain or ceramic with low water absorption (<0.5%). Include a linear or point drain slope.
  • Kitchen backsplash: Subway tile (3×6), mosaic or large format. Grout should be sealed to resist staining.
  • Outdoor use: Frost-resistant, slip-rated (R11 or higher) tiles only. Standard indoor tile can crack in freeze-thaw cycles.

Tile Projects You Can Estimate

Use the calculator for most interior tiling jobs:

  • Bathroom and kitchen floors
  • Shower walls and tub surrounds
  • Kitchen backsplashes
  • Entryways, hallways and laundry rooms
  • Fireplace surrounds and feature walls

Example Tile Estimates

All examples use a 1/8 inch grout gap. Note how the pattern changes the waste allowance and the final count.

Tile count for a 10 ft x 12 ft floor (120 sq ft) with 12 x 24 inch tiles

Example Tile Estimates
LayoutWasteTiles to buy
Straight lay10%65 tiles
Diagonal15%68 tiles
Herringbone20%71 tiles

Why the grout gap matters: 100 sq ft with 12 x 12 inch tiles

Example Tile Estimates
MethodCalculationTiles (10% waste)
Ignoring the grout gap100 tiles + 10%110 tiles
Including a 1/8 inch gap100 / 1.021 sq ft + 10%108 tiles

Figures are rounded up. Always buy from the same production batch and keep a few spare tiles for future repairs.

Tips for Ordering the Right Amount of Tile

  • Measure the room at its widest and longest points. For L-shaped rooms, calculate each section and add them.
  • Use 10% waste for a straight layout, 15% for diagonal and up to 20% for complex patterns.
  • Match the grout gap to your tile: rectified tile allows tighter joints, while non-rectified tile needs wider ones.
  • Subtract large areas that will not be tiled, such as a bathtub footprint or kitchen island.
  • Buy a little extra for future repairs, since dye lots can differ between batches.

Frequently Asked Questions

How many 12×12 tiles do I need for 100 sq ft?

A 12×12 inch tile covers 1 sq ft. For 100 sq ft you need 100 tiles plus waste — order at least 110 tiles (10% waste) for a straight lay, or 115–120 for a diagonal pattern.

How much grout do I need for a tile job?

A rough estimate is 1 lb of grout per 15 sq ft for 12×12 tile with a 1/8 in joint. Smaller tiles and wider joints require more grout. Always buy 10% extra.

What is the best tile size for a small bathroom?

Larger tiles (12×24 or 24×24) with tight grout lines create fewer visual breaks and can make a small bathroom appear larger. Avoid very small mosaic tiles which emphasize the small size.

How much waste should I add for diagonal or herringbone tile?

Around 15% for a diagonal layout and up to 20% for complex patterns such as herringbone, because they create more offcuts at the edges. A straight layout usually needs about 10%.

Can I use the tile calculator for a wall or backsplash?

Yes. Enter the wall length and the height as the second dimension, choose your tile size, and add waste. For a backsplash, subtract any large openings such as windows.

Does the tile calculator include grout?

It gives an estimated grout quantity alongside your tile count. For a more detailed estimate by tile thickness and grout type, use the Grout Calculator.