CONSTRUCTION · FLOORING

Tile Calculator

Estimate the number of tiles, bags of grout, and total cost for your tiling project. Includes grout line allowance and a 15% waste factor for cuts and breakage.

LAST REVIEWED · APR 24, 2026 · BY D. MARQUEZ, P.E.
You need
113 tiles
Project AreaReset
AreaTotal tile area
sq ft
Tile Size
Tile width
in
Tile height
in
Grout widthJoint spacing
Waste factor15% standard for cuts
%
Pricing
Price per tile
USD
Grout (per bag)
USD
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How the tile calculator works

The calculator accounts for both the tile size and grout lines when computing how many tiles you need. It adds grout width to each tile dimension, then divides your total area (plus waste) by the effective tile size. The 15% waste factor covers cuts, breakage during installation, and a few spares for future repairs.

Grout width guidelines

  • 1/16" — rectified (precision-cut) tiles, minimal grout look
  • 1/8" — standard for most floor and wall tile
  • 3/16" — natural stone, handmade tile, larger format on uneven surfaces
  • 1/4" — rustic tile, outdoor applications

Ordering extras

Always order 15% extra at purchase time. Tile dye lots vary — if you go back for more later, the color may not match. Keep leftover tiles for future repairs.

Methodology. Tile area = (tile width + grout width) × (tile height + grout width) in sq ft. Tiles needed = ceil(Area × (1 + Waste%) ÷ Tile area). Default waste is 15% for cuts and breakage. Grout: ~25 sq ft per bag. Standard grout width: 1/8 inch.

Sources

  • TCNA Handbook for Ceramic, Glass, and Stone Tile Installation
  • Tile Council of North America waste factor recommendations: 10–15%
  • Average tile prices: $1–$5/tile for standard ceramic (2026)
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Frequently asked questions

How many 12×12 tiles for 100 sq ft? +
With 1/8" grout lines and 15% waste: effective tile area is about 1.02 sq ft. 100 × 1.15 ÷ 1.02 = 113 tiles. Always round up and add a few extra for cuts at edges.
How much grout do I need? +
A standard 25-lb bag of grout covers about 25 sq ft for 12×12 tiles with 1/8" grout lines. For 100 sq ft, you'd need about 5 bags. Larger grout lines or smaller tiles use more grout per square foot.
What's the best tile size for small bathrooms? +
Large-format tiles (12×24 or 24×24) actually make small bathrooms look bigger — fewer grout lines create a more open feel. For shower floors, use smaller mosaic tiles (2×2 or 1×1) to follow the drain slope.
Can I tile over existing tile? +
Yes, if the existing tile is firmly bonded, level, and the floor can support the added weight. Rough up the surface with 80-grit sandpaper and use a modified thinset. This saves significant time and mess over removal.
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