About Tile Calculator
Calculate how many tiles you need for floors, walls, or backsplashes. Enter room and tile dimensions to get exact tile count, boxes needed, and waste allowance. Free.
How to use
- Enter the area to be tiled: input the room length and width, or enter the total square footage directly if you have already calculated it. For walls (backsplashes, shower surrounds), enter the height and width of the tiled area. The calculator accepts feet, inches, metres, or centimetres.
- Enter the tile dimensions: width and height of a single tile in inches or centimetres. Common floor tile sizes: 12x12 (most popular), 12x24 (modern rectangular), 18x18 (larger format), and 24x24 (large format). Common wall tile sizes: 3x6 (subway), 4x4 (classic), 4x12 (stacked), and 6x6.
- Set your grout joint width (typically 1/8 inch for rectified tiles, 3/16 inch for standard tiles, and 1/4 inch for natural stone) and the waste percentage. The grout gap reduces the effective coverage area of each tile, requiring more tiles to cover the same space.
- Set the waste percentage: 10% for straightforward rectangular installations, 15% for rooms with many cuts around obstacles, and 20% for diagonal (45-degree) installations. Complex patterns like herringbone or chevron may require 15-20% waste depending on tile size and room dimensions.
- View the total number of tiles needed, number of boxes to purchase (based on standard box quantities), and the waste tiles included in the total. The calculator accounts for both grout spacing and waste factor in the final count.
- Compare different tile sizes by running the calculation with each option. Larger tiles cover area faster and create fewer grout lines (easier maintenance) but generate more waste from cuts and may not suit small spaces. Smaller tiles are more material-efficient but require more grout and more labour.
Frequently asked questions
How do I calculate how many tiles I need?
Divide the total area to be tiled by the coverage area of one tile (including grout gap). For 12x12 inch tiles with 3/16 inch grout gaps, effective tile coverage is about 12.19 x 12.19 inches = 1.031 sq ft per tile. For 100 sq ft of floor: 100 / 1.031 = 97 tiles before waste. Add 10% waste: 97 x 1.10 = 107 tiles. Since tiles are sold in boxes (typically 10-15 tiles per box for 12x12), round up to the nearest full box. This calculator handles all the math automatically, including grout gap adjustments and waste factors.
How much tile waste should I plan for?
Standard waste factors: 10% for simple rectangular rooms with few obstacles (the minimum you should ever plan), 15% for rooms with many cuts around cabinets, doorways, and fixtures, and 20% for diagonal installations, herringbone patterns, or rooms with curved walls. Natural stone tiles with colour variation may require 15-20% to allow for selecting matching pieces and discarding stones with undesirable patterns. Large-format tiles (24x24 and bigger) may also need more waste because partial tiles are a larger loss when cut. Always buy all tile from the same production lot to ensure colour consistency.
How many 12x12 tiles do I need for 100 square feet?
A 12x12 inch tile covers exactly 1 square foot, so 100 square feet requires 100 tiles before accounting for grout gaps and waste. With 3/16 inch grout gaps, you need approximately 97 tiles for coverage plus 10% waste = 107 tiles total. If tiles are sold in boxes of 13 (13 sq ft per box), you need 8.2 boxes — round up to 9 boxes. This gives you 117 tiles, providing a comfortable 17% margin. Having extra tiles from the same lot is valuable for future repairs if a tile cracks or chips.
Does grout spacing affect the tile count?
Yes, but minimally for standard installations. Wider grout joints slightly reduce the number of tiles needed because each tile plus its surrounding grout occupies more area. With 12x12 tiles: 1/16 inch grout needs about 100 tiles per 100 sq ft, 1/8 inch needs about 99, 3/16 inch needs about 97, and 1/4 inch needs about 96. The difference is 4 tiles over 100 square feet — minor compared to the waste factor. However, grout spacing affects visual appearance significantly: narrow joints (1/16-1/8 inch) create a more seamless look, while wider joints (1/4 inch) are more traditional and accommodate slight tile size variations.
How do I calculate tiles for a backsplash?
Measure the width and height of the backsplash area. Standard kitchen backsplash is the area between countertop and upper cabinets: typically 18 inches high by the width of the counter run. A 10-foot counter with 18-inch backsplash = 10 x 1.5 = 15 square feet. Subtract any windows or electrical outlets (approximately 0.5 sq ft each). For 3x6 subway tiles (0.125 sq ft each): 15 / 0.125 = 120 tiles + 15% waste for cuts around outlets and edges = 138 tiles. Subway tile boxes typically contain 80-100 tiles. Order 2 boxes for a standard kitchen backsplash. Use the
Square Footage Calculator to measure irregular kitchen and bathroom walls accurately before ordering tile.
What tile size is best for small bathrooms?
Medium-format tiles (12x12 or 12x24) actually make small bathrooms look larger because fewer grout lines create a less busy visual. Very small tiles (1x1 or 2x2 mosaic) create many grout lines that can make a small space feel cluttered, though they are excellent for shower floors where more grout lines improve traction. Very large tiles (24x24) can look disproportionate in a small bathroom and generate significant waste from cuts. The sweet spot for most small bathrooms is 12x24 tiles laid horizontally on walls (elongating the visual) and 12x12 or 2x2 mosaic on the shower floor.
Should I buy extra tiles?
Always buy at least 10% more tiles than calculated, and keep the extras from the original lot. Tile manufacturers produce colours in batches (dye lots), and the same tile ordered 6 months later may have a noticeably different shade. Having matching spares from the original purchase ensures you can replace cracked or chipped tiles years later without a visible colour mismatch. Store extra tiles flat in a dry location with the box label visible so you know the product name and lot number. Many tile retailers accept returns of unopened boxes within 30-90 days, so slightly overbuying carries minimal risk.
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