Tile Calculator – How Many Tiles Do You Need?

วิธีใช้เครื่องคิดเลขนี้

1. ป้อนRoom/Area Length (feet)
2. ป้อนRoom/Area Width (feet)
3. ป้อนTile Length (inches)
4. ป้อนTile Width (inches)
5. ป้อนGrout Joint Width (inches)
6. คลิกปุ่มคำนวณ
7. อ่านผลลัพธ์ที่แสดงด้านล่างเครื่องคิดเลข

How to Calculate How Many Tiles You Need

The basic tile calculation is straightforward:

1. Calculate area: Room area = Length × Width (in square feet)
2. Calculate tile area with grout: Tile area = (Tile length + grout width) × (Tile width + grout width) ÷ 144 (to convert to sq ft)
3. Calculate tiles needed: Room area ÷ Tile area (per tile)
4. Add waste: × (1 + waste percentage)
5. Round up to whole tiles — always round up, never down
6. Calculate boxes: ÷ tiles per box, round up

Never round down on tiles — running short in the middle of a project is a serious problem if tiles are discontinued or from a different dye lot.

Why Add a Waste Factor?

You always need more tiles than the raw square footage calculation suggests because:

• Cuts at edges: Perimeter tiles must be cut to fit the room boundary. Cut pieces generate waste (unusable offcuts).
• Breakage: Tile cuts inevitably break some pieces, especially thin tiles and diagonal cuts.
• Miscuts: Even experienced tilers make measuring and cutting errors.
• Future repairs: Keep 5–10% extra after installation for future replacements if one cracks.
• Layout adjustments: Sometimes tiles need to be repositioned, especially on walls.

Standard recommendation: 10% for straight layouts with simple rooms; 15% for average projects; 20–25% for diagonal layouts, herringbone patterns, or complex room shapes.

Common Tile Sizes and Where They're Used

Choosing the Right Tile Size for Your Space

Tile size affects the perception of room size and complexity of installation:

• Small rooms: Large tiles (18"×18"+) can actually make a small room feel bigger by reducing grout lines; small tiles (4"×4") feel busy and busy can feel smaller
• Large rooms: Large format tiles (24"×24"+) look elegant but require a very flat subfloor and specialized setting materials
• The 1/3 rule: No tile should be cut to less than 1/3 of its original size at room edges — adjust layout starting point to achieve this
• Grout visibility: Smaller tiles = more grout lines = more visual activity = more maintenance

Grout Types and Selection

Choosing the right grout is as important as the tile itself:

• Sanded grout: For joints 1/8" or wider. Standard for floor tile. Provides strength and resistance to cracking in wider joints.
• Unsanded grout: For joints narrower than 1/8". Used for wall tile, glass tile, polished stone (sanded can scratch delicate surfaces).
• Epoxy grout: Highly stain-resistant, no sealing required, very durable. More expensive and harder to apply. Ideal for kitchen backsplashes and commercial applications.
• Grout amount: A 25-lb bag covers approximately 50–100 sq ft depending on tile and joint size.

Tile Setting Materials (Thinset)

Tiles are bonded using thinset mortar (cement-based adhesive). Coverage rates:

• Standard thinset (50 lb bag): covers ~40–50 sq ft for floor tile at 3/8" coverage depth
• For large format tile (18"×18" and larger): use medium-bed mortar, which provides more coverage thickness for back-buttering
• For mesh-backed mosaics: 1/8"–3/16" coverage; a 50-lb bag covers 80–100 sq ft
• White thinset: recommended under light-colored, translucent, or glass tiles

Subfloor Requirements for Tiling

Tile installation requires a solid, flat, stiff subfloor. The L/360 rule: deflection should not exceed the span divided by 360.

• Minimum subfloor thickness for tile: 1.5" total (typically 3/4" plywood + 1/2" cement board)
• Large format tile (18"×18"+): even stricter flatness requirements — no more than 1/8" variation over 10-foot span
• Concrete subfloor: excellent for tile — flat, check for cracks and moisture
• Radiant heat: use flexible uncoupling membrane (Schluter Ditra) and flexible thinset