.Mosaic Tile Calculator 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 1M2 = 1000cm2 2. Correct grout space between Mosaic tiles? If you use the rule of thumb: 10% of the size of mosaic tile with a maximum of 1 cm (10mm) you will hardly ever go wrong. For 10mm to 20mm mosaic tiles we recommend a grout space of approximately 2mm For Mosaic tiles that are less than 10mm try to use a 1.5mm grout space. For Mosaic tiles that are larger than 20mm use the 10% rule but do not ever go larger than 1cm as this will weaken you mosaic. Grout is an essential structural component to mosaic. 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. 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 spaces in the mosaic. More grout lines means more grout and less mosaic tile. If you are cutting the 20mm mosaic tiles in half or smaller you decrease the amount of tiles needed to cover an area by approximately 25% however always add 10% for breakage and wastage. 4. Consider the colour of grout. We use a mosaic rule that says always use a grout that is darker than your mosaic tiles. However you can also use the contrast between grout and mosaic tile to great effect. We recommend that if you are not sure choose a neutral such as cement or silver grey.