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SmartTileCalculator

Tile Calculator

Measure your room, pick your tile size, and this calculator tells you how many tiles and how many boxes to buy — waste for cuts already included. Buying one box short is the most common tile mistake, and dye lots change between orders, so always round up.

Your measurements

Changing the pattern sets a recommended waste factor.

Check the box label; leave 0 to skip.

Tiles to buy

66 tiles

Room area
120 sq ft
Area including waste
132 sq ft
One tile covers
2 sq ft
Boxes needed
9 boxes
Waste applied
10%

Round up to full boxes and keep one spare box from the same dye lot.

Do this math on the job site — in the free app

Smart Tile Calculator for Android: offline, in your pocket, no ads. iPhone version coming soon.

Get it onGoogle PlayComing soon to theApp Store

Tools the pros use for this job

  • Tile Spacers

    500 Pcs 3 mm (1/8 Inch) Plastic Tile Spacers for Stone and Ceramic Tile | 500-Piece Pack,3 mm Spacing,Even Tile Layout,Plastic Construction,Multiple Installation Uses

    500 Pcs 3 mm (1/8 Inch) Plastic Tile Spacers for Stone and Ceramic Tile | 500-Piece Pack,3 mm Spacing,Even Tile Layout,Plastic Construction,Multiple Installation Uses

    Check price on Amazon

    Consistent joints are what make a tile floor read as straight.

  • Tile Wet Saw

    SKIL 7-Inch Wet Tile Saw - 3540-02

    SKIL 7-Inch Wet Tile Saw - 3540-02

    Check price on Amazon

    Rent or buy — you'll cut 15–25% of the tiles in any room.

  • Notched Trowel

    Goldblatt 1/2'' x 1/2'' x 1/2'' Square-Notch Tile Trowel, 11'' x 4.5'' | Stainless Steel Blade, Soft Grip Handle, Square Notch Design for XLarge Ceramic Tile Floor, Pavers, EIFS

    Goldblatt 1/2'' x 1/2'' x 1/2'' Square-Notch Tile Trowel, 11'' x 4.5'' | Stainless Steel Blade, Soft Grip Handle, Square Notch Design for XLarge Ceramic Tile Floor, Pavers, EIFS

    Check price on Amazon

    Match the notch to tile size for full mortar coverage.

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How this calculator works

The math is simple: room area ÷ area of one tile, then add waste. A 12" × 24" tile covers 2 sq ft, so a 120 sq ft floor needs 60 tiles before waste and 66 tiles at 10% waste.

  • Straight/grid layouts: 10% waste.
  • Diagonal: 15% — every perimeter tile becomes two triangles.
  • Herringbone: 20% — the most cut-heavy common pattern.

Buy in full boxes. Keep one unopened box for future repairs; matching tile two years later is usually impossible.

Frequently asked questions

How many 12x24 tiles are in 100 square feet?

Each 12x24 tile covers 2 square feet, so 100 sq ft needs 50 tiles before waste — about 55 tiles with a 10% waste allowance for cuts.

How much extra tile should I buy?

Add 10% for a straight layout, 15% for diagonal, and 20% for herringbone or busy patterns. Add another 5% if the room has many jogs, closets, or curved cuts.

Should I calculate by tile count or square footage?

Buy by square footage in full boxes — that is how tile is sold. Use the tile count to sanity-check the store's box math.

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· Reviewed by the Smart Tile Calculator editorial team