How Many Tiles Do You Need for a Bathroom Floor?

Planning a bathroom tile project? The last thing you want is to run out mid-install or waste money on 30% extra. This guide shows you exactly how many tiles you need.

The Quick Answer

For a 5×8 foot bathroom (40 sq ft) using 12×12 inch tiles:

• Base tiles needed: 40 tiles
• With 10% waste factor: 44 tiles
• Cost estimate: $88–$220 (at $2–$5 per tile)

For a 6×9 foot bathroom (54 sq ft): 60 tiles (with waste).

For a 8×10 foot bathroom (80 sq ft): 88 tiles (with waste).

The Formula

Tile quantity boils down to area calculation plus waste:

Tiles Needed = (Room Area ÷ Tile Area) × (1 + Waste Factor)

Step-by-Step Calculation

1. Calculate room area: Length × Width (in feet)
2. Calculate tile area: Convert tile dimensions to feet, then multiply
3. Divide: Room area ÷ Tile area = base tile count
4. Add waste: Multiply by 1.10 (for 10% waste) or 1.15 (for 15%)

Example: 5×8 Bathroom with 12×12 Tiles

1. Room area = 5 × 8 = 40 sq ft
2. Tile area = 1 ft × 1 ft = 1 sq ft (12” = 1 foot)
3. Base count = 40 ÷ 1 = 40 tiles
4. With 10% waste = 40 × 1.10 = 44 tiles

Bathroom Size Reference Chart

Bathroom Size	Square Feet	12×12 Tiles	12×24 Tiles	6×6 Tiles
Small (5×5)	25 sq ft	28 tiles	14 tiles	112 tiles
Half Bath (5×8)	40 sq ft	44 tiles	22 tiles	176 tiles
Standard (6×9)	54 sq ft	60 tiles	30 tiles	240 tiles
Medium (7×10)	70 sq ft	77 tiles	39 tiles	308 tiles
Large (8×10)	80 sq ft	88 tiles	44 tiles	352 tiles
Master (10×12)	120 sq ft	132 tiles	66 tiles	528 tiles

All quantities include 10% waste factor

Tile Size Comparison

Different tile sizes dramatically affect the number you’ll buy, but not the total coverage.

12×12 Inch (1 sq ft per tile)

Pros:

• Easiest math: one tile per square foot
• Classic look, works in any bathroom size
• Wide variety available

Cons:

• More grout lines to clean
• Can feel busy in tiny bathrooms

Best for: Standard bathrooms (50–100 sq ft)

12×24 Inch (2 sq ft per tile)

Pros:

• Fewer grout lines = easier cleaning
• Makes small bathrooms look larger
• Modern, sleek appearance

Cons:

• Requires flatter substrate (more prep work)
• Fewer tiles = less room for error

Best for: Narrow bathrooms, modern designs

6×6 Inch (0.25 sq ft per tile)

Pros:

• Great for detailed patterns and borders
• Easier to work around curves/fixtures
• Vintage aesthetic

Cons:

• Massive grout line maintenance
• Labor-intensive installation

Best for: Small powder rooms, accent areas

Hexagon & Mosaic Tiles

Specialty shapes are sold by the sheet (typically 1 sq ft per sheet). Calculate the same way:

• Room area ÷ Sheet coverage = Sheets needed
• Add 15–20% waste (irregular shapes = more cuts)

Pro Tips from the Field

1. Always Round Up

If your calculation says 43.7 tiles, buy 44 minimum. Tiles are sold by the piece or box, so you can’t buy 0.7 of a tile.

2. Waste Factors Vary by Pattern

Pattern	Waste Factor
Straight lay	10%
Diagonal	15%
Herringbone	20%
Irregular/mosaic	25%

The fancier the pattern, the more cuts you make, the more waste you generate.

3. Buy From the Same Batch

Tile color varies slightly between production runs. The batch number is printed on the box, so order all tiles at once to ensure color consistency.

If you need to reorder later, bring a tile to the store to color-match.

4. Account for Obstructions

Don’t subtract toilet or vanity footprints from your calculation. Here’s why:

• You’ll tile under the toilet (it sits on the tile)
• You’ll tile under the vanity (for future flexibility)
• The few extra tiles serve as your buffer for breakage

5. Order 5–10 Extra for Future Repairs

Tiles crack. Kids drop things. You’ll want spares for repairs down the road. Store extras in the garage with the batch number visible.

6. Grout Spacing Matters

Grout lines affect coverage, but minimally:

• 1/16” grout lines: Negligible impact
• 1/8” grout lines: Subtract ~2% from tile count
• 1/4” grout lines: Subtract ~5% from tile count

Most bathrooms use 1/8” or 1/16” lines. The waste factor already covers this variance.

Common Mistakes to Avoid

1. Not Accounting for Waste

Scenario: You calculate exactly 40 tiles, order 40 tiles, then crack 3 during installation and need a half-tile cut that splits wrong.

Result: You’re 4 tiles short. The store is closed and your project is stalled.

Fix: Always add at least 10%. It’s cheap insurance.

2. Measuring Wrong

Wrong: Measuring with a tape measure and rounding to the nearest foot.

Right: Measure twice in inches, then convert to feet with decimals.

Example: A bathroom that’s 5 feet 3 inches is 5.25 feet, not 5 feet, which is a 5% error that compounds.

3. Forgetting About Boxes

Tiles are sold in boxes of 10–12 tiles. If you need 44 tiles and boxes contain 10, you’ll buy 5 boxes (50 tiles).

Check the box count before calculating waste. Sometimes the box quantity naturally gives you enough buffer.

4. Ignoring Substrate Prep

Uneven floors lead to the following problems:

• Lippage, where tile edges don’t align
• More broken tiles during installation
• Need for larger grout lines to compensate

If your floor is way off-level, budget for self-leveling compound before buying tiles, because bad prep leads to wasted tiles.

5. Skipping the Layout Test

Before ordering, do a dry layout with these steps:

1. Snap chalk lines for your starting point
2. Lay 10–15 tiles without adhesive
3. Check how the pattern hits walls/corners
4. Adjust starting point if you’ll end with slivers

A good layout minimizes cuts, which means less waste and fewer tiles needed.

Specialty Bathroom Considerations

Walk-In Showers

Shower floors are typically 3×3 to 4×4 feet. For a 4×4 shower floor:

• 12×12 tiles: 18 tiles (with waste)
• Mosaic sheets: 18 sheets (with 15% waste)

Pro tip: Use smaller tiles (2×2 or mosaic) in showers. They follow the slope to the drain better and provide better slip resistance.

Bathroom Walls

If you’re tiling walls too, calculate separately:

Wall area = (Perimeter × Height) - Door/Window openings

Example: 5×8 bathroom with 8-foot ceilings:

• Perimeter = (5+8+5+8) = 26 feet
• Wall area = 26 × 8 = 208 sq ft
• Subtract door (21 sq ft) = 187 sq ft of wall tile needed

Use 15% waste for walls (more cuts around outlets, fixtures).

Heated Floors

Installing radiant heat? The heating mat reduces usable area slightly:

• Wire mats: No impact (wires sit under tile)
• Mat systems: Add 1–2% to tile count for overlap adjustments

Cost Breakdown Example

For a 6×9 bathroom (54 sq ft) with 12×12 porcelain tiles at $3 each:

Item	Quantity	Unit Cost	Total
Tiles	60 tiles	$3	$180
Thinset (1 bag)	1	$25	$25
Grout (1 bag)	1	$20	$20
Tile spacers	1 bag	$8	$8
Sealer	1 qt	$15	$15
Total Materials			$248

Add 10% contingency for broken tiles, extra supplies: $275 total.

Labor (if hiring): $5–$10 per sq ft = $270–$540 additional.

Using the Tile Calculator

For complex bathroom shapes (L-shaped, alcoves, multiple rooms), use our tile calculator for the following features:

• Input exact dimensions in feet and inches
• Add multiple sections (main floor + shower + niche)
• Factor in grout line width
• Get instant tile counts for multiple tile sizes
• Calculate material costs

The calculator automatically applies appropriate waste factors and rounds to box quantities.

Final Checklist

Before you buy, complete this checklist:

• Measured bathroom length and width (in inches)
• Converted to square footage (L × W ÷ 144)
• Selected tile size and pattern
• Applied appropriate waste factor (10–20%)
• Rounded up to nearest full tile/box
• Added 5–10 extra tiles for future repairs
• Verified all tiles from same batch number
• Calculated thinset (1 bag per 50 sq ft) and grout (1 lb per 10 sq ft)

Frequently Asked Questions

How many 12x12 tiles do I need for a 5x8 bathroom?

For a 5x8 bathroom (40 square feet), you need 40 base tiles plus 10% waste factor, which equals 44 tiles total. Since 12x12 tiles cover 1 square foot each, the calculation is straightforward. Add 5-10 extra tiles for future repairs, bringing your order to approximately 50 tiles or 5 boxes (assuming 10 tiles per box).

Should I use 12x12 or 12x24 tiles in a small bathroom?

12x24 tiles make small bathrooms look larger due to fewer grout lines and a more expansive visual flow. They also reduce cleaning time. However, they require a flatter substrate and allow less room for installation errors. For bathrooms under 50 square feet, 12x12 tiles are safer for DIY installation and provide more design flexibility.

How much waste should I add when ordering bathroom tiles?

Add 10% waste for straight-lay patterns, 15% for diagonal layouts, 20% for herringbone, and 25% for irregular or mosaic patterns. The fancier the pattern, the more cuts you make, and the more waste you generate. This accounts for cuts around toilets and vanities, broken tiles during installation, and future repairs.

Do I tile under the toilet or vanity?

Yes, tile under both the toilet and vanity. The toilet sits on top of the tile (not on the subfloor), and tiling under the vanity provides flexibility if you change fixtures later. Don’t subtract these areas from your calculation because the few extra tiles serve as your breakage buffer.

Why do I need to buy tiles from the same batch?

Tile color and finish vary slightly between manufacturing batches even in the same product line. The batch number is printed on each box. Ordering all tiles at once from the same batch ensures perfect color consistency. If you run short and reorder from a different batch later, the color mismatch will be visible.

Use our tile calculator to double-check your math and ensure you order exactly what you need with no shortages and no excess.