This is super important. About 10 months ago, I ordered tile stickers for the very first time for our laundry room. I had them custom cut to the exact size of our ceramic tiles. This was actually a huge mistake that I didn't realize until I ordered from Snazzy Decal on Etsy for Avery's bathroom. Snazzy Decal offered very specific instructions about how to measure for your tile stickers and explained you should order them about 1/8" SMALLER THAN YOUR TILES on each side. That way it leaves a small border all the way around your tile and the sticker is adhering to a perfectly flat surface all the way around (not a slope or bevel which some tiles have slightly.) The tile sticker should not go all the way to or over the grout line at all. You can see below how the tile stickers in Attley's bathroom don't go all the way to the edge. This is what you want! Keep in mind that pretty much all tile sticker companies will custom cut the stickers for you. So even if you only see listings for set sizes (like 12 x 12) that won't work for you, just message them and ask them if they can custom cut your size. The answer will almost certainly be yes and they will explain how you should place your order.