Tile Calculator
Tiles and boxes for a floor or a measured wall, using the real footprint of each tile including its grout joint, with waste for the pattern.
- Grout joint included
- Floor or wall
- Waste by pattern
- Embeddable
Your estimate
12.00 x 24.00 in tile, 10% waste3 boxes
Area
Tiles are area plus waste divided by one tile's footprint including its grout joint, rounded up. Buy from one lot and keep a few spares for repairs.
Counting tiles is more exact than counting square feet, and a tile calculator should be too. Each tile covers its own face plus half of the grout joint around it, so a 12 x 24 in tile with a 1/8 in joint takes up a little more than 2 sq ft. Divide the area to tile by that footprint, add waste for cuts and breakage, and you have the number of tiles; divide by the count per box and you have the order.
How the tile count is worked out
- Area = room floor, less the cut-out corner of an L, or the area you measured for a wall, shower or backsplash.
- Tile footprint = (width + joint) x (length + joint) / 144, in square feet.
- Tiles = area x (1 + waste) / tile footprint, rounded up.
- Boxes = tiles / tiles per box, rounded up.
Picking a grout joint
The tile installation standard, ANSI A108.02, as explained by the Ceramic Tile Education Foundation, says a grout joint must be at least three times the variation in the tiles' size and never less than 1/16 in. For tiles with any side longer than 15 in, the joint should average at least 1/8 in for rectified tile and 3/16 in for calibrated, non-rectified tile.
Rectified tile is ground to an exact size after firing, which is what makes a tight joint possible. If the box does not say rectified, use 3/16 in or more on large tile. The manufacturer's instructions for your tile take priority over a general rule.
Waste allowance for tile
TCNA and ANSI publish no waste percentage, so this is common guidance rather than a standard: buy at least 10% extra for a straight or offset layout and up to 20% for herringbone or diagonal patterns. Large-format tile can need more, because one broken tile is a bigger share of the order.
Keep the leftover tiles. Matching a discontinued tile years later is often impossible.
Frequently asked questions
Primary references
Manufacturer and industry guidance used to check this article.
- Want credit card grout joints? Check tile industry standardsCeramic Tile Education Foundation
- Installing tile, large format guidanceMarazzi
- How much tile do I need?Bob Vila
Product instructions, tested assemblies and local code take priority over general guidance.