Flooring Calculator
Flooring Calculator
Estimate tiles or planks for a rectangular floor area. Enter room dimensions, optional non-floor areas, and your flooring piece size with grout joint. The calculator gives you order area plus piece count with waste — and optional box quantities.
Flooring Calculator
Estimate tiles/planks for a rectangular floor area (minus openings) with waste allowance
Results
Enter values above to calculate
Tile Module vs Tile Size
The tile "module" includes the grout joint on each edge. The calculator uses module area for accurate piece counts that match a real laid floor.
Step-by-Step Formulas
1. Gross Floor Area
Measure to the longest wall-to-wall dimension in each direction. For L-shaped or irregular rooms, break the space into rectangles, calculate each, and sum the areas.
2. Subtract Non-Floor Areas
Subtract fixed islands, hearths, or built-in furniture bases that won't receive flooring. If uncertain, leave as 0 and use a slightly higher waste allowance.
3. Add Waste Allowance
Waste covers offcuts, breakage, and layout. 5–10% suits straight installs. Budget 10–15% for diagonal runs or herringbone patterns where offcut rates are higher.
4. Convert Area to Pieces
Tile counts use the "module" area (tile + grout joint). Plank counts use the plank face area (no joint for click-lock products). Results round up to whole pieces.
Waste Allowance by Pattern Type
| Layout pattern | Recommended waste |
|---|---|
| Straight run (grid or brick bond) | 5–8% |
| Straight run (many cuts / irregular room) | 8–12% |
| Diagonal (45°) tile or plank | 12–15% |
| Herringbone or chevron | 15–20% |
| Complex pattern (multiple sizes) | 18–25% |
Typical Grout Joint Width by Tile Size
| Tile size | Typical grout joint |
|---|---|
| Mosaic (≤50 mm) | 1–3 mm |
| Small (50–150 mm) | 2–3 mm |
| Medium (150–300 mm) | 3–5 mm |
| Large (300–600 mm) | 3–6 mm |
| Extra-large (600 mm+) | 5–10 mm |
* Always follow tile manufacturer and tile-setter guidelines for joint width — rectified tiles can take narrower joints than pressed/non-rectified tiles.
Worked Example
A 5 m × 4 m room, no non-floor areas, 10% waste. 600 × 600 mm tile with 3 mm grout joint.
Planks, Boxes and Expansion
Flooring estimating is straightforward area work, with three details that decide whether the job goes smoothly:
- Order by the Box: Flooring is sold in boxes of fixed coverage. Rounding up to whole boxes is the real order quantity, and the leftovers become your repair stock.
- Waste Depends on Layout: A straight lay in a rectangular room wastes little. Diagonal installations, herringbone, and rooms with many jogs push waste from 10% to 20% or more.
- Expansion Gaps Are Not Optional: Wood and laminate need a perimeter gap — typically 1/4 to 1/2 in — hidden by skirting. Flooring fitted tight to the walls buckles as soon as humidity rises.
Benefits of Using This Calculator
Example Calculations
Three scenarios worked through step by step:
Example 1 — Living Room, Straight Lay
Room 20 ft × 15 ft, box covers 22 ft², 10% waste.
Area = 20 × 15 = 300 ft²
With 10% waste = 300 × 1.10 = 330 ft²
Boxes = 330 ÷ 22 = 15 boxes exactly
Result: 15 boxes, about 30 ft² of spare material
Example 2 — Diagonal Installation
Room 16 ft × 14 ft, box covers 20 ft², 20% waste for diagonal.
Area = 16 × 14 = 224 ft²
With 20% waste = 224 × 1.20 = 268.8 ft²
Boxes = 268.8 ÷ 20 = 13.4 → 14 boxes
Diagonal lay cuts every board at the perimeter
Example 3 — Open Plan With Hallway
Main room 24 × 18 ft plus hall 12 × 4 ft, box covers 24 ft², 12% waste.
Main = 24 × 18 = 432 ft²; hall = 12 × 4 = 48 ft²
Total = 432 + 48 = 480 ft²
With 12% waste = 480 × 1.12 = 537.6 ft²
Boxes = 537.6 ÷ 24 = 22.4 → 23 boxes
Installation Tip
Installation Tip
Let flooring acclimatise in the room where it will be installed for 48 to 72 hours before you open a single box, with the heating running as it normally would. Boards fitted straight off a cold delivery truck shrink as they warm, opening gaps at every joint within weeks.
Frequently Asked Questions
- What waste percentage should I use for flooring?
- For simple rooms and straight installs, 5–10% is common. For diagonal or herringbone patterns, 10–15% is safer.
- Should I subtract kitchen cabinets or fixed islands?
- If flooring will not be installed under fixed items, you can subtract those areas. If uncertain, leave as 0 and use a slightly higher waste allowance.
- Why does tile count include grout joint thickness?
- Using tile module size (tile + grout joint) matches real layouts more closely since every tile has a joint on each edge in the finished installation.
- Do plank counts include an expansion gap?
- No — the expansion gap is covered by skirting/base board and does not require extra planks. The calculator estimates plank face area only.
- How much extra flooring should I order?
- Ten percent for a straight lay in a simple rectangular room, 15% where the room has alcoves or several doorways, and 20% for diagonal or herringbone patterns. Keep the offcuts — you will want them for future repairs.
- How do I calculate flooring for an irregular room?
- Split the space into rectangles, calculate each separately, and add them together. An L-shaped room is two rectangles; a room with a bay is a rectangle plus a trapezoid. Measure at the widest point of each section.
- Do I need an expansion gap around the edges?
- Yes for wood, laminate, and floating vinyl — typically 1/4 to 1/2 in at every wall and fixed object, covered by skirting or quarter-round. Glued-down and fully bonded tile do not need one, but floating floors absolutely do.
- Should I buy by square feet or by boxes?
- Calculate in square feet, then convert to whole boxes using the coverage printed on the carton. Partial boxes are not sold, so the box count is always what you order, and it is usually slightly more than your waste-adjusted area.
- Which direction should the planks run?
- Conventionally along the longest wall or toward the main light source, which makes the room read longer and hides seams. Structurally, planks over a wood subfloor should run perpendicular to the joists unless there is a plywood underlayment.
- Do I include closets in my measurement?
- Include them if you intend to floor them, which most installations do. Measure each closet as its own small rectangle and add it to the total — they are easy to overlook and collectively add up in a bedroom-heavy layout.