BuildRuler

Build & DIY estimates

Tile calculator

Quick answer: Tiles needed = room area ÷ area of one tile, plus waste. Add 10% for straight layouts and 15% or more for diagonal or herringbone patterns. Example: a 10 × 12 ft floor (120 sq ft) with 12 × 12 in tiles needs 120 tiles plus 10% waste, so buy 132.

  • Manufacturer bag yields · published coverage rates
  • Updated
  • Reviewed by Alex · How we calculate

Add 10% waste for straight layouts and 15% or more for diagonal or herringbone patterns.

Waste allowance

Add 10% for straight-set tile and 15% for diagonal layouts or large-format tile. Breakage and cuts around toilets, vents and corners use more than you expect, and matching the same dye lot later is hard.

Worked example

A 60 sq ft bathroom floor with 12 × 12 in tiles needs 60 tiles; with 10% waste, 66. At 10 tiles per box, buy 7 boxes. Grout coverage depends on joint width and tile size, so check the grout bag's chart.

Frequently asked questions

How much extra tile should I buy?

10% for straight lays; 15%+ for diagonal.

How do I convert tile size to square feet?

Multiply the length and width in inches and divide by 144: a 12 × 24 in tile is 2 sq ft.

Should I include the grout lines?

Not for estimating; the waste allowance covers it.