How to Calculate How Many Tiles You Need

Getting the tile quantity right before you buy is one of the most practical things you can do before a renovation. Buy too little and you face a second trip — and risk the new batch not matching the original. Buy too much and you have spent extra money on tiles sitting in a storeroom.

This guide walks through the exact calculation method we use at our showroom in Bentong, with real examples for floors and walls.

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The Basic Formula

The core calculation is straightforward:

Step 1: Calculate the room area in square feet or square metres

For a rectangular room:

Area = Length × Width

For an L-shaped room, split it into two rectangles and add the areas together.

Step 2: Add wastage

You always need more tiles than the exact area. Tiles are cut during installation, some break, and some are set aside as spares for future repairs. The standard wastage allowance in Malaysia:

Tile Layout	Wastage to Add
Straight grid (horizontal/vertical)	10%
Diagonal (45°) layout	15–20%
Complex room with many corners	15%
Large format tiles (60×120cm)	12–15%

Formula with wastage:

Tiles needed = Room area × (1 + wastage percentage)

Step 3: Convert to number of boxes

Tile packaging tells you the coverage per box (usually in m² or sq ft). Divide your total area by the coverage per box, then round up to the nearest whole box.

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Example 1: Bathroom Floor

Room size: 2m × 2.5m
Tile size: 30×60cm (0.18m² per tile)
Layout: Straight grid
Wastage: 10%

1. Room area: 2 × 2.5 = 5m²
2. Add 10% wastage: 5 × 1.10 = 5.5m²
3. Tiles per box: Each box covers 1.44m² (8 tiles of 30×60cm)
4. Boxes needed: 5.5 ÷ 1.44 = 3.82 → round up to 4 boxes

Total: 4 boxes (32 tiles)

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Example 2: Kitchen Floor with Diagonal Layout

Room size: 3m × 4m
Tile size: 60×60cm
Layout: Diagonal (45°)
Wastage: 15%

1. Room area: 3 × 4 = 12m²
2. Add 15% wastage: 12 × 1.15 = 13.8m²
3. Tiles per box: Each box covers 2.16m² (6 tiles of 60×60cm)
4. Boxes needed: 13.8 ÷ 2.16 = 6.39 → round up to 7 boxes

Total: 7 boxes (42 tiles)

Note: Diagonal layouts waste significantly more because every border tile must be cut at an angle. If you are tiling on a budget, stick to a straight layout.

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Example 3: Bathroom Walls

Wall tiling involves the same formula, but you need to subtract openings (windows, doors, mirrors) and think about each wall separately.

Room: 2m × 2.5m bathroom, tiling all four walls to ceiling height 2.7m
Tile: 30×60cm wall tiles
Openings: Door (0.9m × 2.1m), one window (0.6m × 0.9m)

1. Total wall area: perimeter × height = (2+2.5+2+2.5) × 2.7 = 9m × 2.7m = 24.3m²
2. Subtract door: 0.9 × 2.1 = 1.89m²
3. Subtract window: 0.6 × 0.9 = 0.54m²
4. Net wall area: 24.3 − 1.89 − 0.54 = 21.87m²
5. Add 10% wastage: 21.87 × 1.10 = 24.06m²
6. Coverage per box: 1.44m² (8 tiles)
7. Boxes: 24.06 ÷ 1.44 = 16.7 → round up to 17 boxes

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Converting Between Square Metres and Square Feet

Many tile suppliers in Malaysia list prices in square feet (sq ft), while rooms are often measured in metres.

1 m² = 10.764 sq ft
1 sq ft = 0.0929 m²

Quick reference:

Metres	Square Feet
1m²	10.76 sq ft
5m²	53.8 sq ft
10m²	107.6 sq ft
20m²	215.3 sq ft
50m²	538.2 sq ft

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Common Room Sizes in Malaysian Homes

These are rough area estimates for typical Malaysian terrace house rooms. Use them as a starting point and always measure your actual room.

Room	Typical Floor Area
Master bathroom	4–7 m²
Common bathroom	2.5–4 m²
Kitchen (wet)	8–15 m²
Kitchen (dry, open plan)	10–20 m²
Living room	15–30 m²
Bedroom	10–16 m²
Carpark (1 car)	12–18 m²
Balcony	4–10 m²

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How to Measure Your Room Accurately

For rectangular rooms:

• Measure the longest wall length
• Measure the longest wall width (perpendicular to length)
• Multiply to get area

For L-shaped rooms:

• Split into two rectangles
• Measure each rectangle separately
• Add the two areas

For bathrooms with a floor trap:

• Measure the full floor area as a rectangle, then subtract the floor trap (typically negligible — less than 0.01m²)
• The floor trap will be cut around during installation; this is already accounted for in the wastage allowance

Tips:

• Always measure from wall to wall, not from skirting to skirting
• For walls, measure floor-to-ceiling height (not wall-to-window height, unless you are only tiling a section)
• Take three measurements of each dimension and use the largest — walls are rarely perfectly straight

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Why You Should Always Buy Extra

We recommend buying 10–15% extra beyond your calculation for two reasons:

1. Batch matching

Tiles from the same production batch have consistent colour and texture. Tiles from a different batch — even the same product code — can have subtle but visible differences in shade. If you run short and return to buy more tiles, the new delivery may not match perfectly.

2. Future repairs

Bathroom and kitchen tiles get chipped, cracked, or damaged over years of use. A matching tile from the same batch stored in your storeroom is the easiest repair you will ever do. A discontinued tile with no matching stock means replacing a much larger area.

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Quick Reference: Tiles Per Box vs Coverage

Different tile sizes pack differently into boxes. Here is a guide for common Malaysian tile sizes:

Tile Size	Tiles Per Box (typical)	Coverage Per Box
20×20cm	25 tiles	1.00 m²
30×30cm	16 tiles	1.44 m²
30×60cm	8 tiles	1.44 m²
60×60cm	4 tiles	1.44 m²
60×120cm	2 tiles	1.44 m²
10×10cm mosaic	1 sheet	~1.00 m²

Note: Packaging varies by brand. Always check the box label for the actual coverage stated by the manufacturer.

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Frequently Asked Questions

How much wastage should I add for a bathroom?

10% for a straight layout. If the bathroom has many internal angles — shower niches, unusual shapes, or a diagonal layout — increase to 15%.

What if I am tiling both floors and walls?

Calculate each surface separately with its own wastage allowance. Do not add floor and wall areas together before calculating wastage.

Can I return unused tiles if I buy too many?

This depends on the supplier's policy. At our showroom, we can exchange unopened boxes from the same batch if you have unused stock. Check before you buy whether your supplier allows returns — this affects whether you should buy conservatively or generously.

My contractor says a different quantity than my calculation. Who is right?

Always reconcile the difference. Contractors sometimes round up significantly to ensure they have enough stock. If the contractor's figure is 20% or more above your calculation, ask them to explain where the extra quantity is going.

Do I calculate tiles in m² or sq ft?

Either works. Match the unit used by your supplier. Malaysian suppliers often quote prices in sq ft while rooms are measured in metres. Use the conversion factor: 1m² = 10.76 sq ft.

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Low Brother Ceramics can help you calculate the exact tile quantity for your project. WhatsApp us at 016-383 1925 with your room measurements and we will confirm the quantity and check current stock.