How to estimate tile for a floor or wall
Measure area, add a sensible waste factor, then round up to whole boxes.
Tile estimates are mostly math, but most surprises come from two practical details: waste and how the product is packaged. Even a simple room needs cuts at walls, doorways, and edges, and those offcuts are not always reusable. Coverage per box also varies by tile size and thickness, and it can change between a field tile box, mosaic sheets, and trim pieces.
A good estimate starts with measuring only the surfaces you will actually tile, then adding a waste factor that matches your layout (straight vs diagonal/pattern) and the complexity of the space (niches, benches, many corners). Once you have total tile area with waste, convert to boxes using the label coverage and round up so you finish in one batch.
Step-by-step: tile math
- Measure the tiled area. For floors, add each room (and closets if they get the same tile). For walls, measure each rectangle (width x height) and add features like shower niches, half walls, or backsplash sections.
- Decide what you are not tiling. Subtract only truly untiled areas that are large enough to matter (big windows, large built-ins). Many people keep small cutouts (outlets, small vents) in the total and let waste cover the difference.
- Pick a waste factor that matches your layout and risk. Around 10% is common for straight-lay rooms with few obstacles. Use more for diagonal layouts, herringbone, lots of corners, large-format tile in small rooms, or strict pattern/vein matching (project dependent).
- Convert area to boxes using the product label coverage and make sure units match (sq ft vs m²). If you have multiple products (field tile, mosaics, bullnose/trim), estimate each separately because coverage and waste differ.
- Round up to whole boxes and consider keeping at least a little extra for breakage during cutting and for future repairs. If returns are allowed, keeping one unopened box from the same batch is often the easiest insurance against discontinuation and color variation later.
Practical tips
- Do a quick layout plan before ordering. Avoiding tiny edge slivers and deciding where cuts land can change waste more than the raw square footage.
- Patterns (diagonal, herringbone) and many obstacles create more unusable offcuts. In small or oddly shaped rooms, geometry drives waste more than area.
- Account for details that are not part of field tile coverage: edge trim, metal profiles, thresholds, and any decorative borders. These often need separate quantities and can delay a job if missing.
- Buy enough at once and keep the batch/lot consistent when possible. Small size and shade differences between lots can make grout lines and leveling harder to keep consistent.
Tile waste and layout tips
Tile waste is driven by layout: more corners, patterns, and smaller pieces mean more cuts. For walls, niche shelves, benches, and plumbing penetrations can also increase waste.
If appearance matters (most installs), you’ll want to buy enough from a consistent dye lot. That makes getting the waste factor right more important than the last decimal place of area.
- Use a higher waste factor for diagonal/herringbone layouts and many corners.
- Consider a separate estimate for mosaics, borders, and trim pieces.
- Keep a small number of spares for future repairs (same lot if possible).
Tile overage (waste) starter guide
Overage is mostly cuts and layout. If you need a consistent dye lot, buying enough upfront is usually cheaper than matching later.
| Install | Typical overage | Notes |
|---|---|---|
| Straight floor | 10% | Increase for many corners |
| Diagonal / patterns | 15–20% | More cuts and waste |
| Walls with niches | 15–25% | Penetrations add cuts |
| Large format | 10–15% | Fewer pieces, breakage matters |
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