Guide 03 · Floors
Flooring & Tile Calculator
Convert floor area into whole packs of flooring or boxes of tiles, with grout joints and layout waste built in. Then compare the main floor types before you choose.
From floor area to order quantity
Flooring is sold in packs that cover a fixed area, and tiles in boxes of a fixed count. Neither can be bought by the exact square metre, so every order involves two roundings: adding waste for cuts and breakages, then rounding up to whole packs. The calculators above do both. The number to take to the merchant is the pack or box count, not the area.
Waste allowances by layout
How much extra to order depends mainly on the laying pattern and the shape of the room. The figures below are widely used rules of thumb rather than fixed standards, so defer to the installer or the product instructions where they differ.
- Straight lay in a simple rectangular room: around 5–10%.
- Diagonal lay: often 10–15%, because every edge piece is a triangular cut.
- Herringbone or chevron: commonly 15–20%, with more for small rooms.
- Many corners, pipes or door frames: add a few percent on top of the pattern allowance.
Floor types compared
| Type | Pros | Cons | Good fit |
|---|---|---|---|
| Laminate | Scratch-resistant wear layer, click fitting, wide range of looks | Many products dislike standing water; can sound hollow without good underlay | Living rooms, bedrooms, hallways |
| Engineered wood | Real wood surface, more stable than solid wood, some can be sanded | Limited refinishing on thin wear layers; can dent | Living spaces, some underfloor heating setups |
| Solid wood | Can be sanded and refinished many times; long life | Moves with humidity; usually unsuitable for wet rooms | Dry living areas, period homes |
| Luxury vinyl tile / plank | Water-resistant, warm and quiet underfoot, thin profile | Needs a very flat subfloor; can be marked by heavy furniture | Kitchens, bathrooms, utility rooms |
| Carpet | Warm, soft, reduces noise between floors | Harder to clean; sold in roll widths that can create waste | Bedrooms, stairs, snugs |
| Porcelain / ceramic tile | Very durable, water-proof, easy to clean | Cold and hard underfoot; slower, more skilled installation | Bathrooms, kitchens, hallways |
Working out tiles, including the grout joint
The calculator treats each tile as its own size plus one grout joint in each direction. A 600 × 600 mm tile with a 3 mm joint occupies 603 × 603 mm, giving roughly 2.75 tiles per square metre before waste. That small joint matters more with small tiles: on mosaics or 100 mm tiles, joints account for a much larger share of the surface.
Large-format tiles mean fewer joints and a cleaner look, but they demand a flatter subfloor and more careful handling, and each breakage wastes more material. Rectified tiles, with precisely ground edges, allow narrower joints; tiles with slightly irregular edges usually need wider ones.
The materials around the floor
Remember the supporting items: underlay for floating floors, adhesive and grout for tiles, levelling compound for uneven subfloors, threshold strips where floors meet, and trims or beading around the edge. Wood-based floors generally need an expansion gap around the perimeter so they can move with humidity; the skirting or a scotia bead then covers it. The materials and waste guide helps with these extras.
Floating or bonded?
Floating installation
Quick and DIY-friendly, it can often go over an existing sound floor, and individual boards may be replaceable. However, it can feel less solid, and it needs expansion gaps and suitable underlay.
Glued or bonded installation
A solid, quiet feel underfoot, and often preferred for large areas or tiles. The downsides are that it is slower, messier and harder to remove later, and subfloor preparation is critical.