What size tile? Is there a pattern to the tile? Is there many tile that have to be cut? Are the tiles being set in a pattern? How picky do you want them to be? Do you want to pay them the downtime and remobilization if you do not have enough tile on hand when they need it? Can the overage be returned?

With a simple shape like subway tile you need almost no overage. With large tiles or patterns you need A LOT more.

One floor is a star and cross tile. 6” each. yeah there will be a lot of cuts with something like that, so i expect to need an extra foot or so along the margin. Fireclay QCs every tile they sell and sorts out any imperfections, so if its good enough to pass their standard, it should be good enough for the tile layer. At $43 a sqrft for the tile cost alone I would happily eat the extra labor costs if we have to remobilize rather than double my tile budget. Interstingly, Fireclay says they wont take back overages, but do offer returns. My guess is that any unopened box can probably go back.

The other floor is a sheeted mosaic in 12” square sheets. Same deal, an extra foot around and 20% overage still brings us to a much lower number than that provided.

12” mosaic I usually do a 10% overage since it’s something you can measure accurately.