How much tile do you need? You’ll know in just 4 quick steps . . .
1. Measure Your Surface
Measure the dimensions of the surface you would like to mosaic and calculate the area using the formulas from elementary school:
RECTANGLE AREA = length x width
TRIANGLE AREA = 1/2 x width x height
CIRCLE AREA = 0.785 x diameter x diameter
Keep in mind that 1 ft2 is 144 in2.
If you get your answer in square inches, just divide by 144 to get the answer in square feet.
We have help with the formulas at the bottom of the page if you need it.
2. Look Up An Estimate
Now look up an estimate of the number of mosaic tiles you need based on square footage. Except for 8mm and 3/8 inch tile, these estimates assume a grout spacing of 1/16 inch between the tiles. The 8mm and 3/8 inch numbers are based on a smaller grout gap of 1/32 inch. The first three columns refer to mosaic marble stone of different types. The fourth column refers to 3/4-inch glass mosaic tile. Remember that 1 ft2 is 144 in2.
# of Square Feet
3. Are you cutting the tiles?
Cutting a mosaic tile in pieces theoretically decreases the amount of tile you need. How is this so? You will have more pieces, so there will be more grout lines in the mosaic. More grout lines means more grout and less mosaic tile. The effect can be significant. For example, it requires 218 of the 3/4″ glass mosaic tiles to cover 1 square foot with a grout spacing of about 1/16 inch, but if you cut the tiles into pieces, you might only need 200 tiles. On the other hand, people who cut tile probably should budget a little extra as waste. That’s why we use 218 per square foot as a rule of thumb for 3/4″ mosaic tile.
4. Consider the Spacing Between Tiles
Tile coverage is determined as much by the grout spacing between the tiles as it is by the area you are covering. All of the calculations in our tables assume a grout spacing of 1/16″ between the mosaic tiles. This spacing is common with stone, ceramic and glass mosaic tile because it ensures enough grout will penetrate between the tiles and seal over the adhesive underneath. It also provides enough gap between the tiles to ensure that the tiles are visually distinct at a distance so that the mosaic does not look like one big piece. For advice about choosing a grout color, see our page of Mosaic Instructions.
Note that 3/4″ glass mosaic tile sometimes comes face-mounted on paper so that the installer can glue the whole sheet to a wall and then peel the paper off the face of the tile and then grout. These sheets are made according to metric standards, so that the grout spacing is slightly larger than 1/16″. Typically there are 225 tiles mounted on a sheet that is 1.15 square feet. Our metallic glass mosaic tiles and swirled glass mosaic tiles are cut from such sheets. Most artists remove the tiles from the sheets before using, so this doesn’t matter.