How to Calculate How Many Tiles You Need (And Avoid Costly Mistakes)

Planning a tile project should feel exciting—not intimidating. Whether you’re refreshing a small powder room, designing a spa-like shower, or laying sleek large-format porcelain across an open-concept main floor, the single most important planning step is knowing how many tiles to order. Get this right and everything else—from budgeting to installation—becomes smoother, faster, and far less stressful.

This long-form guide from The Tile Shoppe walks you through every scenario with clear methods, step-by-step examples, and practical tables you can reference while measuring. You’ll learn how to measure any space (even odd ones), convert areas into tile counts and boxes, account for grout joints and pattern layouts, and add a smart waste factor that protects your project from surprises without overspending.

No fluff—just a thorough, professional process you can trust.

What You’ll Get From This Guide

• A simple master method that works for floors, walls, showers, stairs, and backsplashes

• Coverage tables for common tile sizes and shapes

• How to convert square footage to tile counts and boxes (with rounding rules)

• Waste factor recommendations for real-world installations

• Pattern-specific notes for diagonal, herringbone, chevron, and basketweave

• A complete master bathroom calculation from start to finish

• A printable measurement worksheet and final ordering checklist

• A concise FAQ to demystify common pitfalls

Why Accurate Tile Calculation Matters

Under-ordering risks mid-project delays and color tone mismatches if you need to purchase later from a different production lot. Over-ordering ties up budget and leaves you hauling heavy boxes back to the store. The goal is the sweet spot: enough tile to cover real-world cutting, layout adjustments, and a few future repairs—without overbuying.

Key outcomes of a correct calculation:

• Smooth, uninterrupted installation

• Consistent shade and calibration across the job (single lot)

• Less waste and better budgeting

• A few spare pieces for future repairs or add-ons

The Master Formula (Works for Most Rooms)

1. Measure the longest length and widest width of each area.

2. Area (sq ft) = Length (ft) × Width (ft)

3. Total Project Area = Sum of all areas (subtract openings or obstacles if tile won’t go behind/under them).

4. Adjusted Area = Total Project Area × (1 + Waste Factor)

5. Tile Count = Adjusted Area ÷ Coverage per tile

6. Box Count = Tile Count ÷ Tiles per box → Round up to the next whole box

Tip: If you work in inches, multiply (length in inches × width in inches) ÷ 144 to get square feet.

Tools That Make Measuring Easy

• 25-ft tape measure (rigid blade, good hook)

• Notepad + pencil (sketch your space; pencil helps revise)

• Graph paper (1 square = 6" or 1'; makes complex spaces manageable)

• Calculator (your phone is fine)

• Laser measurer (optional, handy for high walls and large spaces)

• Blue painter’s tape (mock up borders, pattern starts, and transition lines)

Understanding the Units (Square vs. Linear)

• Square footage (sq ft): used for floors, walls, and most field tile

• Linear footage (lf): used for trims, listellos, bullnose, edge profiles, and coping

• Grout joints: affect layout and the visual grid; they slightly reduce coverage per tile in a tight layout but are usually handled by your waste factor rather than exact math

Coverage: Common Tile Sizes

Below is a quick-reference coverage table for popular sizes. Coverage per tile assumes nominal dimensions; always check the product’s exact specs on the box or product page for final ordering.

A. Squares & Rectangles

Formula recap:
Area per tile (sq ft) = (W in inches ÷ 12) × (L in inches ÷ 12)

B. Mosaics (per sheet)

Many mosaic sheets are 12×12 in and cover ≈1.0 sq ft per sheet (allowing for interstitial grout space). Always check the sheet’s listed coverage.

Some mesh-mounted sheets with heavy pattern spacing will list coverage slightly under 1.0 sq ft. Use the exact box or product spec for final math.

How Many Boxes? (Typical Ranges)

Packaging varies. As a rule of thumb:

• 12×12: often ~10 sq ft/box

• 12×24: often ~10 sq ft/box (5 pieces)

• 24×24: often ~16 sq ft/box (4 pieces)

• Planks (8×48): often ~8–10.7 sq ft/box (varies)

Always read the product label or product page for the exact pieces per box and sq ft per box—and round up.

Step-by-Step: Measuring Real Spaces

1) Simple Rectangle (Floor or Wall)

• Measure length and width (in feet)

• Multiply: Area = L × W

Example: 8 ft × 6 ft bathroom floor = 48 sq ft

2) Complex Rooms

Break into rectangles and sum the areas:

• L-shapes: split into two rectangles

• Halls with nooks: treat each change as its own rectangle

• Irregular curves: approximate with rectangles; add a little extra waste

Example (L-shape):

• A: 10 ft × 8 ft = 80 sq ft

• B: 6 ft × 4 ft = 24 sq ft

• Total = 104 sq ft

3) Subtract Fixed Obstacles (when appropriate)

If a vanity or built-in cabinet will sit on top of the tile and you’re not tiling beneath it, subtract its footprint.

Example: 10×12 ft room = 120 sq ft. Vanity 2.5×4 ft = 10 sq ft.
Adjusted area = 110 sq ft before waste.

Pro note: Many installers do tile under moveable vanities to avoid awkward cuts and to allow future style changes. If in doubt, don’t subtract.

4) Walls with Windows/Doors

• Measure height × width of each wall

• Subtract the area of openings you will not tile

Example: 8 ft × 10 ft wall = 80 sq ft; door 2 ft × 3 ft = 6 sq ft
Net wall area = 74 sq ft

5) Showers (Multiple Walls + Niche)

Treat each wall as a rectangle.

Example:

• Back wall: 4 ft wide × 7 ft high = 28 sq ft

• Side wall: 3 ft deep × 7 ft high = 21 sq ft (×2) = 42 sq ft

• Niche: 1.5 ft × 2 ft = 3 sq ft (subtract)
  Total = 28 + 42 − 3 = 67 sq ft

6) Stairs

Calculate treads and risers separately, then add.

Typical dimensions: tread ≈ 11" deep × 36" wide; riser ≈ 7" high × 36" wide

Many projects trim treads and risers with nosing/bullnose. Plan the linear footage for trim separately (see “Borders & Trims” below).

For a 13-step flight: 13 × 4.5 = 58.5 sq ft (before waste)

Grout Joints: Do They Change the Math?

Grout joints (e.g., 1/16", 1/8") create small gaps that slightly reduce the number of tiles per area. In practice, the effect is usually covered by your waste factor. If you’re working with ultra-tight joints and a layout that pushes coverage to the edge, consider a 2–3% reduction in net coverage. For most jobs, apply the standard waste factor and proceed.

Waste Factor: Your Real-World Safety Net

Waste accounts for:

• Layout cuts at edges and corners

• Off-squares and out-of-plumb walls

• Breakage during cutting or handling

• Pattern starts and directional changes

• A few spare pieces for future repairs

Recommended Waste Factors

If your space has lots of inside/outside corners, odd angles, or you’re mixing multiple sizes/patterns, lean high on the waste range.

Formula:
Adjusted Area = Total Area × (1 + Waste % as decimal)

Example: 110 sq ft × 1.15 = 126.5 sq ft

Converting Area to Tiles and Boxes

Step A: Find coverage per tile (table above or product spec).
Step B: Tile Count = Adjusted Area ÷ Coverage per tile
Step C: Box Count = Tile Count ÷ Tiles per box → Round up

Example:

• Adjusted area: 126.5 sq ft

• Tile size: 12×24 (2.0 sq ft per tile)

• Tiles needed: 126.5 ÷ 2.0 = 63.25 tiles → 64 tiles minimum

• If 5 tiles/box: 63.25 ÷ 5 = 12.65 boxes → 13 boxes

Always round up boxes. You can return unopened, full boxes per store policy.

Pattern Layouts: What Changes?

Diagonal (45°)

• Same area math; increase waste to 15–20% (up to 25% for large-format)

Herringbone

• Alternating 90° layout with 45° cuts at perimeters

• Expect 20–25% waste

• Plan the pattern start line carefully so cut pieces land at perimeter edges, not across a main view

Chevron

• Similar to herringbone, but tiles meet in “V” seams

• 20–25% waste; precise angle cuts at edges

Basketweave / Pinwheel / Mixed Sets

• Waste 15–25% depending on repeat and edges

• Make a scaled sketch on graph paper to visualize how the repeat lands at walls and openings

Borders, Accents, and Trims (Linear Footage)

Linear footage planning is separate from field tile square footage.

1. Measure the path length of the border or trim (in feet or inches).

2. Convert to pieces using the listed length of each trim piece.

3. Add waste (10–15%), plus extras for corners, mitered returns, and terminations.

Example:

• Perimeter run: 168 inches

• Border piece length: 6 inches

• Pieces: 168 ÷ 6 = 28

• Add 15% waste: 28 × 1.15 = 32.2 → 33 pieces

Don’t forget special trims: bullnose, quarter-rounds, cove base, edge profiles, and stair nosing.

Backsplashes (Small Area, Many Obstacles)

Because backsplashes include outlets, switches, and windows, you can either:

• Quick method: Calculate the full rectangle and apply 10–15% waste, or

• Precise method: Subtract openings, then apply 10% waste

Example:

• Length = 12 ft; height = 18 in (1.5 ft)

• Area = 12 × 1.5 = 18 sq ft

• With 10% waste: 18 × 1.10 = 19.8 sq ft

• Using 3×6 subway (0.125 sq ft/tile): 19.8 ÷ 0.125 = 158.4 tiles

• If 50 tiles/box: 158.4 ÷ 50 = 3.168 → 4 boxes

Real-World Examples (Start to Finish)

Example 1: Simple Kitchen Floor

• Room: 12 ft × 15 ft = 180 sq ft

• Tile: 18×18 (2.25 sq ft/tile)

• Layout: Straight; Waste: 10%

• Adjusted area: 180 × 1.10 = 198 sq ft

• Tiles: 198 ÷ 2.25 = 88.0 tiles

• If 4 tiles/box (9 sq ft/box): 198 ÷ 9 = 22.0 → 22 boxes

Example 2: Bathroom Wall + Shower

• Walls total (after subtracting one small window): 78 sq ft

• Shower walls (with one 1.5×2 ft niche): 67 sq ft

• Total wall area: 145 sq ft

• Tile: 4×12 (0.3333 sq ft/tile)

• Complexity: Fixtures + niche → Waste: 20%

• Adjusted area: 145 × 1.20 = 174 sq ft

• Tiles: 174 ÷ 0.3333 ≈ 522 tiles

• If 15 tiles/box (≈5 sq ft/box): 174 ÷ 5 = 34.8 → 35 boxes

Example 3: Patio With Herringbone 12×24

• Area (from sectioning rectangles): 200 sq ft

• Tile: 12×24 (2.0 sq ft/tile)

• Pattern: Herringbone → Waste: 25%

• Adjusted area: 200 × 1.25 = 250 sq ft

• Tiles: 250 ÷ 2.0 = 125 tiles

• If 5 tiles/box (10 sq ft/box): 250 ÷ 10 = 25 → 25 boxes

Example 4: Staircase (13 Steps)

• Per step (tread + riser): ≈ 4.5 sq ft

• 13 steps: 13 × 4.5 = 58.5 sq ft

• Tile: 6×6 (0.25 sq ft/tile)

• Waste (many cuts): 25%

• Adjusted area: 58.5 × 1.25 = 73.125 sq ft

• Tiles: 73.125 ÷ 0.25 = 292.5 tiles → 293–300 tiles (round sensibly to whole boxes)

• Add bullnose/edge trim: measure total step edges (linear feet) and order trim accordingly

Special Shapes (Hex, Octagon, Triangle)

When using specialty shapes, always check the manufacturer’s listed coverage. If not available, approximate from geometry and add extra waste for edge terminations.

Edges of hex/octagon layouts generate more small cuts. Plan borders or transitions to “frame” the field cleanly.

Large-Format Tile (LFT) Considerations

Tiles in the 24×24, 12×24, 8×48 range (and larger) give a modern, seamless look—but they’re heavier, require flatter substrates, and often demand more precise cuts. This can increase breakage during cutting and the number of “remakes” at edges.

• Use 15–20% waste if your layout has many obstacles or you’re running complex patterns

• Plan movement joints and transition strips according to best practices

• Dry-lay the first few rows to confirm pattern starts and cut sizes at the perimeter

Quick-Reference Formulas (Keep These Handy)

• Area (sq ft) = (Length in inches × Width in inches) ÷ 144

• Adjusted Area = Area × (1 + Waste %)

• Tile Count = Adjusted Area ÷ Area per Tile

• Box Count = Tile Count ÷ Tiles per Box → Round up

• Linear Pieces = (Total inches needed) ÷ (inches per piece) × (1 + Waste %)

Common Mistakes (and How to Avoid Them)

1. Forgetting waste (or choosing too little)

   • Minimum 10% for simple rooms; more for patterns/obstacles

2. Rounding down boxes

   • Always round up; unopened full boxes can typically be returned

3. Not checking boxes for a single lot

   • Keep all boxes from the same lot for color calibration consistency

4. Subtracting too many obstacles

   • Many pros tile under floating vanities and appliances to avoid awkward edges

5. Ignoring wall plumb and floor flatness

   • Out-of-square rooms and uneven floors increase cuts; add waste accordingly

6. Underestimating trim needs

   • Measure linear footage for borders, bullnose, and edge profiles separately

7. Skipping a dry layout

   • Dry-lay a row or two to confirm joint widths, pattern start, and cut sizes

Complete Project Walkthrough (Master Bathroom)

Scenario:

• Floor: 8 ft × 10 ft (80 sq ft) with a 2 × 3 ft fixed vanity footprint (subtract 6 sq ft)

• Shower walls: 3 ft × 4 ft × 7 ft high (two side walls + back wall), plus a 1.5 × 2 ft niche

• Backsplash: 6 ft run × 1.5 ft high

1) Areas (before waste)

• Floor adjusted (subtract vanity): 80 − 6 = 74 sq ft

• Shower walls: Back (4×7=28) + Side (3×7=21) × 2 = 28 + 42 = 70 sq ft

  • Subtract niche (1.5×2=3): 67 sq ft

• Backsplash: 6 × 1.5 = 9 sq ft

2) Choose tile + waste factors

• Floor tile: 12×12 (1.0 sq ft/tile), standard layout → 15% waste

• Shower walls: 4×12 (0.3333 sq ft/tile), obstacles + niche → 20% waste

• Backsplash: same 4×12, simple → 10% waste

3) Apply waste

• Floor: 74 × 1.15 = 85.1 sq ft

• Shower: 67 × 1.20 = 80.4 sq ft

• Backsplash: 9 × 1.10 = 9.9 sq ft

4) Convert to boxes (example packaging; use actual product specs)

• Floor 12×12 (≈10 sq ft/box): 85.1 ÷ 10 = 8.51 → 9 boxes

• Walls 4×12 (assume ≈2.66 sq ft/box if 8 pieces/box; or ≈5.0 sq ft/box if 15 pieces—use the real box):

  • Combine shower + backsplash: 80.4 + 9.9 = 90.3 sq ft

  • If 2.66 sq ft/box: 90.3 ÷ 2.66 = 33.94 → 34 boxes

  • If 5.0 sq ft/box: 90.3 ÷ 5.0 = 18.06 → 19 boxes

• Listello / trim (6" pieces around 14 lf = 168"):

  • Pieces = 168 ÷ 6 = 28; with 15% waste = 33 pieces

Match your calculation to the actual box coverage listed on each SKU at The Tile Shoppe.

Measurement Worksheet (Fill-In Template)

Room / Area Name: __________________________

A. Floor/Wall Sections

• Section 1: L = ___ ft, W = ___ ft → Area = _______ sq ft

• Section 2: L = ___ ft, W = ___ ft → Area = _______ sq ft

• Section 3: L = ___ ft, W = ___ ft → Area = _______ sq ft

• Add more as needed…

Subtotal Area: _______ sq ft

B. Subtractions (openings/obstacles not tiled):

• Item 1: L = ___ ft, W = ___ ft → Subtract _______ sq ft

• Item 2: L = ___ ft, W = ___ ft → Subtract _______ sq ft

Net Area: _______ sq ft

C. Waste Factor: % → Adjusted Area = Net × (1 + Waste) = ** sq ft**

D. Tile Selection: Size __________, Area per tile __________ sq ft

• Tiles needed: Adjusted Area ÷ Area per tile = _______ tiles

• Tiles per box: __________ → Boxes needed: _______ → Order: _______ boxes (rounded up)

E. Trims / Borders / Listellos (linear):

• Total path: _______ inches ÷ piece length (in) _______ = _______ pieces × (1 + waste) = _______ pieces

Final Checklist (Before You Order)

• Measured every section and sketched the plan

• Decided whether to tile under vanities/appliances or subtract footprints

• Selected waste appropriate to layout and patterns

• Converted to tiles and boxes, rounding up

• Calculated trims and borders by linear footage

• Verified sq ft/box and pieces/box per SKU

• Confirmed all boxes are the same production lot

• Set aside a few spares for future repairs

• Reviewed return policy for unopened full boxes

• Scheduled delivery/pickup to align with installation timeline

Frequently Asked Questions

Q1: Should I subtract the area under a vanity or kitchen base cabinets?
If the vanity is permanently built-in and you’re certain you’ll never change it, you can subtract its footprint. Many homeowners tile under floating vanities and appliances to avoid awkward transitions and to future-proof the space. When in doubt, keep it simple and don’t subtract.

Q2: Do grout joints change how many tiles I need?
Not usually in a way that’s worth recalculating tile counts. Your waste factor (10–25% depending on complexity) naturally covers small differences created by joint width.

Q3: How many extra tiles should I keep after installation?
At least a handful—more for large spaces or unique shades/patterns. Those spares are invaluable for a chip or crack years later.

Q4: Why is my waste factor higher for patterns?
Angled cuts (diagonal, herringbone, chevron) generate more offcuts, and you’ll make more “start” cuts to align repeats. 20–25% is normal for these layouts.

Q5: What about mixing sizes or adding a border?
Calculate each field separately (by size), then add linear footage for borders. Apply waste to each, especially if sizes interlock.

Q6: My room isn’t perfectly square. Does that matter?
Yes—out-of-square walls mean more edge adjustments. Add a bit more waste and dry-lay your first rows to confirm cut sizes at both ends of a run.

Q7: Can I just order by square footage and ignore tile counts?
You can for an estimate, but final ordering should use actual box coverage and pieces per box so you don’t get caught short.

Pro Tips for a Cleaner Install and Cleaner Math

• Dry-layout the first course to verify where cuts will land. If you get a sliver at the end, center your layout or shift the start line.

• For large-format tile, check substrate flatness; excessive lippage corrections during install often increase breakage—hence higher waste.

• Transitions (doorways, room breaks) are natural places to shift a pattern. Mark these in blue tape before you begin.

• When ordering edge trims and bullnose, mock up corners and returns; miter cuts consume extra pieces.

• For showers, plan where listellos, niches, and benches intersect the grid so you aren’t forced into awkward miters or tiny slivers.

Put the Method to Work (Quick Scenario Recap)

You: 10×12 room; 4×12 wall tile; a 24×24 floor tile in the adjacent hall; herringbone in the foyer.

1. Break areas into rectangles; compute square feet.

2. Subtract only what truly won’t be tiled.

3. Choose waste: 10–15% straight lay; 20–25% for pattern rooms.

4. Convert to tiles and boxes from the product’s real packaging.

5. Round up, confirm same lot, and keep a few spares.

That’s it—the process scales to any project.

Ready to Order?

Bring your measurements and sketches into The Tile Shoppe or browse our selection online at https://tileshoppes.com. Match your chosen tiles to the tables above, confirm each SKU’s sq ft per box and pieces per box, and we’ll help you finalize a confident order—from a single consistent lot—so your installation looks flawless and stays on schedule.

If you’d like a second set of eyes, our team can review your math, help refine waste percentages based on the exact layout, and suggest trims and finishing pieces to complete the look.

Measure well, plan smart, and tile beautifully.