Doing this measure is not easy at all because you can make a little mistake and the amount of material you are going to buy will be either too much or too less.
One way would be to make all the measurements for the bathroom or kitchen and take them to the store where someone will calculate you exactly how many wall or floor tiles do you need.
There is also the possibility of a professional tiler that will do the job for you.
Using an online calculator, you can easily find out the number of tiles and without having to leave your home.
Here is how to use the online calculator:
Measure both the length and the width of the area you are going to tile. Then round the numbers to the nearest foot or meter. After that, choose a size for the tiles from the available ones: 3X3, 4X4, 6X6, 8X8, 10X10, 12X12, 14X14, 16X16, 18X18, 24X24.
First, enter the results for the length and width into the calculator and then the tile size. After you push the calculate button, you will find out exactly how many tiles do you need for every area that needs to be tiled. There will be also a 10% cutting and breakage that the calculator will allow in the calculation.
With the information provided, you can shop online for the best ceramic tiles that fit your house and your budget.