I have a wall that is 25 sq ft, the tiles I want to put on it are "24.5 length by 18.5" width. How many tiles will I need to cover the 25 sq ft?

Depends on what you haven't told us... first... is this homeowork... and why are you only putting tile on one wall?

It's a backsplash for a kitchen

You do the math... but you have to account for cuts... the partial tiles because upi can only get two patial tiles out of one as long as they total to less than one tile in size... you also have to account for the gap for grouting depending on your spacing choice.

You have to allow for mistakes... and some extras to keep for future repairs.

You need more if you've never done this before... you also need to account for bullnose tile if at any point you have an outside edge like a window our a corner that would have an exposed edge.

Basically measue the unobstruceted wall area... see how many tile fit that... and round up the amount of tile that need cut. You can put a cut edge into a inside corner.. or up against the cabinets... but you want uncut edges by the counter or against any other tile.

Sounds confusing? I'm sure... but these factors you need to consider before buying the tile for a count..

Also make sure ALL the time has the same date code or they might not match... make sure the store has plenty on hand if you really screw up and need more.

Safest bet for me is laying one like this out on paper, to scale, at say 1/2" or 1/4" to one foot. Then make yourself a tile out of cardboard (at the same scale of course) and you can experiment and balance it out the way you want, count the tiles needed, add a few for mistakes or flaws, and have fewer worries. You can also keep track of waste from each tile that is cut and possibly use it where it will work best.

Start the tile from the center of the wall... from the bottom working up to to the left and right..

Thank you.

A kitchen back splash are usually between 18'' and 19'' from counter to bottom of cabinets. This would equate to on 18.5 '' tile high. Measure length and divide by 2. This will tell you how many tile you need. Add at least 5 more for cuts and future repairs.

Chuck

Thanks.