Enter room and tile dimensions to estimate materials, including wastage, optional non-tiled cutouts, and estimated cost.
How this is calculated
Cutouts are subtracted from the room area, then the wastage allowance is applied to the remaining area, then the result is divided by the area of one tile.
tiles = ceil( ( (room L × room W) − cutouts ) × (1 + wastage%) ÷ (tile L × tile W) )boxes = ceil( tiles ÷ tiles_per_box ) (only when "tiles per box" is set)All units are converted to feet internally before computing area.
10% wastage is the trade default for straight-laid square tiles. Bump to 15% for diagonals; 20% for pattern layouts (herringbone, basket-weave) or large-format tiles 24 inches and up.
How much wastage should I plan for tile?
10% is the trade default for straight-laid square tiles. Bump to 15% for diagonal layouts. Push to 20% for pattern layouts (herringbone, basket-weave, or anything with directional grain), and for large-format tiles 24 inches and up, where every cut is bigger and harder to reuse.
Should I round up to whole boxes?
Yes. Dye lots can vary between batches, so order all your tile at once and round up to whole boxes. Keep at least one spare box for future repairs.
Does this calculator account for grout joints?
No; it uses the nominal tile size to compute count. Grout joints (typically 1/16″ to 1/4″) effectively cover slightly more area per tile, but the wastage allowance absorbs the difference.
What is a good breakage allowance for tile?
Ten percent covers a straight lay in a square room. Go to fifteen for a diagonal or herringbone pattern, or for a room with several cutouts, because both produce more offcuts you cannot reuse. Large-format tile breaks more in handling, so allow a little more again.
How do I convert square feet to boxes of tile?
Divide your square footage by the coverage printed on the box, then round up, because suppliers sell whole boxes and dye lots change between orders. The calculator does that step for you once you enter the tile size, and it adds the breakage allowance before it rounds.
How many tiles to order, and why you buy them all at once
Two numbers decide a tile order: how many tiles the floor takes, and how many spares you carry home so a repair years later still matches. If you are working out an order for a floor or a wall, set the waste factor for your layout first and the count follows.
A worked example
Say you are tiling a 10 ft by 12 ft floor, which is 120 square feet net, with 12 by 24 large-format tiles at 2 square feet each. Large format cuts more, so use 20 percent waste: 120 times 1.20 is 144 square feet. Divide by 2 square feet per tile and you need 72 tiles. That already carries your cutting allowance, so you are not ordering thin.
Common mistakes
- Using 10 percent waste on a layout that cuts more. A straight lay is fine at 10 percent, but a diagonal wants 15 and a pattern or large-format run wants 20, because more tiles meet a cut edge.
- Ordering in two trips. Tile is made in dye lots, and a second batch bought later rarely matches the first, so buy the whole job in one order.
- Skipping the spare box. A tile cracked years down the road needs a match you can no longer buy, so a leftover box from the original lot is your repair kit.
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Tile always needs more than the square footage suggests, once you count cuts and breakage. This handles that, and it is a live example of a tool I can build into your site. Book a discovery call
On the same job you may also need paint coverage or drywall sheets. Every calculator here is free and runs in your browser.
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