Posted by Dev Trafficon
on January 02, 2026
Few moments in a renovation feel quite as wonderful as seeing a tiled surface come together with blissful intentionality. The lines are clean, the cuts are precise, and the material sits comfortably within the space; a true blend of artistry and practicality that would feel right at home on r/oddlysatisfying. Yet behind every successful tile installation is a far less glamorous essential step: calculating how much tile you actually need.
Order too little and you risk delays, mismatched batches or compromised layouts. Order too much, and you may find yourself stuck with a costly surplus of tiles long after the project is complete (see: every handyperson's garage). Like most aspects of good design, accuracy here is about balance, foresight and restraint.
Whether you are tiling a bathroom floor, a kitchen splashback or a full-height shower, the principles remain consistent. What changes is the level of complexity.
At VICTiles, whether you are a DIY renovator or a professional in the construction and interior decor space, we want to make sure that you have the tools required for your job. So, to ensure that you don't end up stuck halfway through a tile project without the materials to finish things off, let's take a look at how to get your calculations right.
Start With the Space, Not the Tile
It's easy to get ahead of yourself when preparing a new bathroom look or kitchen aesthetic. Unfortunately, a lot of mistakes tend to come from focusing on the form, without really considering the function. In other words, before thinking about formats, finishes or patterns, begin with the area itself. Measuring accurately is the foundation of every tile calculation, and can honestly save you a lot of money.
For placing floor tiles, measure the floor's length and width of the room and multiply the two to establish the total area (Area = Length x Width). In Australian homes, it is common for rooms to include recesses, nib walls or partial returns, so resist the temptation to round up early. Instead, break irregular spaces into smaller rectangles, calculate each area separately, and then combine the totals.
Thankfully, wall tiles follow the same logic, though the measurements shift vertically. Each wall should be measured individually, with height multiplied by width. Shower recesses, niches and ledges should be included, as these areas often require additional cutting and attention during installation.
At this stage, measurements should be recorded in square metres for local consistency. If your original dimensions are taken in millimetres, converting early helps avoid confusion later.
Understanding Tile Coverage
Once the total surface area is known, attention turns to the tile itself. Tile coverage is determined by the size of an individual tile, multiplied by how many tiles fit into one square metre.
For example, a single tile measuring 600 by 600 millimetres covers 0.36 square metres. Divide your total floor or wall area by this figure to establish the base quantity of tiles required.
So, as a simple breakdown:
Room = 100 Square Metres
Tile = 0.36 Square Metres
100 ÷ 0.36 = 277.78 Square Metres
It is worth noting that many tiles are sold by the box rather than individually, with each box clearly stating its total coverage. In practice, most calculations end here, with total area divided by coverage per box. This is often the cleanest and most reliable method, particularly for porcelain and large-format tiles.
Allowing for Waste, Cuts and Reality
No tile installation exists without waste. Cuts around corners, floor wastes, vanities and door frames all require additional material. Even the most experienced installers will factor this in from the outset.
As a general guide, a waste allowance of 10% is appropriate for straight-lay patterns in simple rooms. Increase this to 15% when working with diagonal layouts, herringbone patterns or rooms with multiple angles and interruptions. Natural stone installations may also warrant a slightly higher allowance, as variation and selection play a greater role.
This buffer also provides insurance for the future. Keeping a small number of spare tiles from the original batch can be invaluable should repairs or replacements be required years down the line.
Floors and Walls Require Different Thinking
While the calculation method remains consistent, walls typically demand more tiles than floors of the same area. Vertical applications involve more cuts, more visual scrutiny and often decorative trim elements that do not appear on floors.
External corners, open tile edges and transitions between surfaces may require bullnose pieces, metal trims or decorative liners. These are usually sold by the length or by individual pieces, rather than by area, and should be measured separately in linear metres.
Failing to account for trims early can lead to last-minute compromises that detract from an otherwise refined finish.
Patterns, Grout and Tile Behaviour
Tile layout has a meaningful impact on quantity. A simple grid pattern is efficient and predictable. Offset or staggered layouts increase cutting. More expressive patterns, such as herringbone or chevron, can significantly increase waste, particularly with rectified tiles.
Grout spacing also plays a subtle role. While grout lines do not dramatically change total quantities, tighter joints and rectified edges demand greater precision. In practice, this reinforces the importance of maintaining a sensible buffer rather than attempting to calculate to the last tile.
When Calculators Help and When They Do Not
Online tile calculators can be useful for early planning and budgeting, particularly when comparing tile formats or estimating overall cost. However, they assume ideal conditions and simple layouts.
For bathrooms, kitchens, and other detail-heavy spaces, manual measurement remains the more reliable approach. Where uncertainty exists, consulting a tile specialist or installer before ordering can prevent costly miscalculations.
A Measured Step Toward a Better Outcome
Calculating tile quantities is not merely a simple administrative task. It is part of the broader discipline of thoughtful design and careful execution that can be the defining factor in whether a space looks luxurious and intentional. By measuring accurately, allowing for reality and respecting the material, you set the groundwork for a result that feels calm, resolved and enduring.
In the context of contemporary Australian interiors, where quality materials and longevity are increasingly valued, taking the time to get this step right is not just practical; it is essential.