How to Calculate How Many Tiles You Need: A Step-by-Step Guide

How to Calculate How Many Tiles You Need: A Step-by-Step Guide

Planning a home renovation is an exciting project, but nothing stalls progress quite like running out of tiles halfway through the job. On the flip side, buying far too many means wasting money that could have been spent elsewhere on your new bathroom.
At Thorva Tile and Bathrooms, we want to make your DIY or renovation project run as smoothly as possible. Calculating your tile quantities doesn’t require advanced maths. By following this simple, step-by-step guide, you will order the exact right amount of [Link to your Floor Tiles collection: floor tiles] or [Link to your Wall Tiles collection: wall tiles] every single time.
Step 1: Measure Your Space (The Formula)
Before you start browsing designs, grab a tape measure, a notepad, and a pen. You need to break your walls or floors down into simple rectangles.
  1. Measure the Width: Measure the horizontal distance of the surface in metres.
  2. Measure the Length (or Height): Measure the vertical height for walls, or the length for floors, in metres.
  3. Multiply Them: Multiply the width by the length to get the total area in square metres (m²).
The Formula: Width (m) x Length (m) = Total Area (m²)
Example: If your bathroom floor is 2 metres wide and 3 metres long, your calculation is:
2m x 3m = 6m²
If your room isn’t a perfect rectangle (e.g., it has an L-shape or an alcove), split the floor into smaller, manageable boxes. Calculate the area of each box separately, then add them all together at the end.
Step 2: Subtract Obstacles (Optional)
If you are tiling a large wall that features a massive window or a set of bi-fold doors, you don’t want to pay for tiles you won’t use.
  • Measure the width and height of the window or door.
  • Multiply them to get the square meterage of the opening.
  • Subtract that number from your total wall area.
Note: For standard bathroom obstacles like a vanity unit, toilet, or bath, we highly recommend tiling behind and underneath them. This ensures a waterproof seal and allows you to change your bathroom layout easily in the future without leaving gaps in the tiling.
Step 3: Account for the "Waste Factor" (Crucial)
Never order the exact square meterage of your room. Tiles must be cut to fit into corners, around pipes, and along edges. When a tile is cut, the leftover piece is often unusable.
To prevent running short, you must add a waste percentage to your total area before buying:
  • Standard Grid Layout: Add 10% for traditional linear patterns.
  • Complex Layouts (Herringbone, Chevron, Diagonal): Add 15% because these patterns require significantly more intricate cuts at angles.
How to calculate your total with waste:
Multiply your baseline area by 1.1 (for 10% waste) or 1.15 (for 15% waste).
Using our earlier example of a 6m² floor for a standard grid layout:
6m² x 1.1 = 6.6m² total to order
Step 4: Convert Area into Tile Boxes
Tiles are rarely sold individually; they are boxed by the square metre. Every product page on the Thorva Tile and Bathrooms website lists exactly how many square metres a single box covers.
To find out how many boxes to add to your cart:
  1. Take your total area figure (including the waste factor).
  2. Divide it by the coverage provided in one box.
  3. Always round UP to the nearest whole number.
Example: You need 6.6m² of tiles. The premium [Link to a specific tile product: Thorva Porcelain Tile] you love covers 1.44m² per box.
6.6 ÷ 1.44 = 4.58
Since you cannot buy a fraction of a box, round 4.58 up to 5 boxes.
Pro Tips from the Thorva Team
  • Keep a Spare Box: Once your tiling is complete, always keep one full box tucked away in the loft or garage. If a pipe leaks years down the line, or you accidentally drop something heavy and crack a tile, you will have exact replacements ready.
  • Watch Out for Batch Numbers: Tile manufacturers produce tiles in batches, and subtle colour shade variations can happen between different production runs. If you don't order enough at the start and have to buy one more box later, it might come from a different batch and slightly mismatch your existing wall. Buying all your boxes at once prevents this completely.
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