RenoPlanMaker · 5 min read
Tile quantity starts with the area you will cover, then adds an allowance for cuts, breakage and any spare tiles you want to retain. Divide that adjusted area by one tile’s area and round up. Finally, round the tile count to complete boxes. The layout and supplier’s pack information should confirm the final order.
Measure the tiled area, not just the room
For a rectangular floor, multiply length by width. For walls, measure each section’s width and height, then add the sections together. Divide an L-shaped floor into rectangles. Write the dimensions down so the installer can check your quantities against the planned layout.
Confirm where tile will stop before subtracting anything. A bath panel, kitchen unit or appliance footprint should only be excluded if the agreed design genuinely leaves that area untiled. Do not subtract a movable item simply because it is sitting there on measuring day.
Use consistent units for the tile dimensions
In imperial mode, the calculator accepts room dimensions in feet and tile dimensions in inches. It divides tile length × width by 144 to convert square inches to square feet. In metric mode, room dimensions are metres and tile dimensions are centimetres, converted to metres before multiplication.
A 30 × 30 cm tile covers 0.09 m². A 12 × 12 in tile covers 1 sq ft; it is not exactly the same size as the metric tile. Read the actual product specification, and check how the supplier defines coverage for mosaics, mixed-size packs or modular patterns.
Choose a waste allowance from the layout
Waste covers material that cannot be used after cuts and breakage. RenoPlanMaker suggests testing 10% for a straightforward layout and 15–20% for more complex patterns. These are calculator planning assumptions, not guarantees for every room or tile format.
Large tiles in a narrow room, diagonal cuts and many corners can change the usable offcuts. Daltile’s pattern guidance warns against assuming rooms are perfectly square and advises rounding quantities upward. Ask the installer to check the layout before treating any percentage as a final order.
- Confirm the pattern and starting point before ordering.
- Check whether offcuts can be reused elsewhere.
- Decide whether repair spares are included in your allowance.
- Increase or reduce the allowance only with a clear reason.
Worked example: tiles and complete boxes
Imagine a 10 × 8 ft floor using 12 × 12 in tiles and a 10% waste allowance. The floor is 80 sq ft; adding 10% gives 88 sq ft. Each tile covers 1 sq ft, so the tool estimates 88 tiles.
With 10 tiles per box, 88 ÷ 10 = 8.8, rounded up to 9 boxes. You actually purchase 90 tiles. At a hypothetical $5 per sq ft, the calculator’s tile-cost line is $440 for 88 tiles, while 90 purchased tiles would cost $450 at that same rate. Check the pack price before budgeting the final checkout total.
Check boxes, batch information and returns
Use the tiles-per-box value from the chosen product, not an assumed pack size. If the supplier sells by square metre per box, confirm the equivalent tile count and stated coverage. Mixed-format packs may need a supplier-specific calculation rather than the single-size tool.
Ask about shade or batch identifiers and order matching material where applicable. Check the return policy before counting on a refund for spare boxes. Keep usable leftovers and the product label for future repairs, but do not assume the identical tile will remain available indefinitely.
Tile cost is not the whole tiling budget
The calculator’s tile price excludes adhesive, grout, preparation, trims, waterproofing, tools and installation. Adhesive and grout quantities depend on the product, tile format, substrate and joint dimensions. Use their manufacturers’ coverage instructions rather than estimating them as a fixed fraction of tile cost.
For showers, Schluter explains that tile and grout are not waterproof. Include the specified waterproofing assembly in the scope and have the installer confirm compatible materials and required checks. A quantity calculation does not establish that a floor or wall is suitable for tiling.
Make a final check before placing the order
Give the installer your dimensions, tile specification, pattern and proposed box quantity. Confirm any borders, niches, stairs or separate wall areas that need their own calculation. Compare the checked order with your overall bathroom or renovation budget before paying.
The goal is not to buy the smallest possible number of tiles. It is to buy a justified quantity that can complete the agreed layout without relying on an uncertain second order. Save the measurements and assumptions with the supplier’s invoice for a clear record.
Frequently asked questions
Should I always add exactly 10% extra tile?
No. Ten percent is a planning starting point for simple layouts. The actual allowance depends on cuts, format, breakage risk and the spares you want.
Does the tile-cost result include full-box rounding?
No. It prices the calculated tile count; the boxes line separately rounds up. Use the supplier’s complete-box price for the final spend.
Can the calculator estimate wall tiles?
Yes, for a rectangular surface: enter its width and height as the two surface dimensions. Calculate separate sections and products individually.
Sources & further reading
Examples are illustrative; calculator presets are planning assumptions, not verified local quotes. Safety and consumer guidance: