DIYCalcLab

Topic · Tile estimating

Tile quantities: layout waste, grout and thinset

By DIYCalcLab Editorial Team · Updated

This page is the method, not the tool list. Tile count is the area divided by one tile plus one grout joint, then a layout waste factor, then whole boxes. Grout and thinset use their own coverage charts. The longer waste-factor essay stays on the tile guide.

  • Free
  • No sign-up
  • Transparent calculations
  • US & metric

Open Tile calculator →All tile calculators

Start here

Core calculators

Start with the tool that matches your job. Each page shows the formula, defaults, shopping list and sources.

Quantity formulas

  • Tiles = area ÷ ((tile length + joint) × (tile width + joint))
  • Tiles needed = that count × (1 + waste), rounded up
  • Boxes = tiles needed ÷ tiles per box, rounded up. Spare = tiles purchased − tiles needed
  • If waste is blank, the tile calculator uses straight 10%, offset 12%, diagonal 15%, herringbone 20%

Variables

Joint
Added once to each side of the tile before dividing the area
Waste
Cuts and breakage. Whole-box spare is a separate remainder, not a second waste percent
Grout and thinset
Not this tile count. Grout follows joint width and tile thickness; thinset follows trowel notch
Sizes the tile calculator already accepts
FromTo
12 × 12 in tileDefault imperial tile, with a 1/8 in joint
30 × 30 cm tileDefault metric tile, with a 3 mm joint
US thinset exampleVersaBond chart: 90 sq ft per 50 lb bag with a 1/4 × 1/4 in notch (minimum)
UK nameTile adhesive is the usual name for thinset; the calculator is the same page

Worked examples

Each example uses the same inputs as the linked calculator. The link loads those inputs; the page URL without parameters stays the canonical.

10 × 8 ft floor, 12 × 12 in tile, 1/8 in joint, straight layout

Imperial · 10 ft × 8 ft · tile 12 × 12 in · joint 1/8 in · pattern straight · waste blank (10%) · 10 tiles per box

  1. Area = 80 sq ft
  2. Before waste = 78.4 tiles
  3. With 10% for a straight layout → 87 tiles needed
  4. Buy 9 boxes = 90 tiles. Spare from full boxes = 3

Result: 87 tiles needed. Purchase: 9 boxes (90 tiles), 3 spare from rounding up.

Open this example in the calculator →

3 × 2.5 m floor, 30 × 30 cm tile, 3 mm joint, straight layout

Metric · 3 m × 2.5 m · tile 30 × 30 cm · joint 3 mm · pattern straight · waste blank (10%) · 11 tiles per box

  1. Area = 7.5 m²
  2. Before waste = 81.7 tiles
  3. With 10% for a straight layout → 90 tiles needed
  4. Buy 9 boxes = 99 tiles

Result: 90 tiles needed. Purchase: 9 boxes (99 tiles).

Open this example in the calculator →

Layout waste is not one percent

  • Calculator default when the waste field is blank: straight 10%, offset 12%, diagonal 15%, herringbone 20%.
  • Cited: Daltile recommends purchasing approximately 10% more tile than you anticipate needing. That matches the straight-layout default and does not set the herringbone default.
  • The tile guide’s table is wider (offset 10–12%, herringbone 15–20%, plus more for large format and small rooms). This page does not collapse that table into the calculator defaults.
  • Grout coverage is quoted from a sanded-grout data sheet (a 25 lb bag covering 348 sq ft of 12 × 12 × 3/8 in tile with a 1/8 in joint). Thinset coverage is quoted from a mortar chart (90 sq ft per 50 lb bag at a 1/4 × 1/4 in notch). Use those calculators for a job quantity.

Limits

  • Pavers are a landscaping quantity. Ceiling tiles are a grid quantity in the drywall category. Neither uses this layout waste.
  • Pattern defaults are installer ranges stored in the calculator, not a code minimum.
  • Backsplash, grout and thinset keep their own pages and their own quantities.

Related calculators

Guides

Quick questions

Which layout percent does a blank waste field use?

Straight 10%, offset 12%, diagonal 15%, herringbone 20%. Daltile’s recommendation to buy approximately 10% more tile matches the straight default and does not set the herringbone default. The tile guide’s table is wider (offset 10–12%, herringbone 15–20%, plus more for large format and small rooms). This page does not collapse that table into the calculator defaults.

Do grout and thinset come out of the tile count?

No. Tile count is area divided by one tile plus one joint, then the layout factor, then whole boxes. Grout follows joint width and tile thickness. The sanded-grout sheet cited here gives 348 sq ft from a 25 lb bag for 12 × 12 × 3/8 in tile with a 1/8 in joint. Thinset follows the trowel notch. The VersaBond chart cited here gives 90 sq ft per 50 lb bag at a 1/4 × 1/4 in notch. Use those calculators for a job quantity.

Does this method cover pavers or ceiling tiles?

No. Pavers stay on the landscaping paver calculator. Ceiling tiles stay on the drywall ceiling-tile calculator. Neither uses this layout waste. This page is the tile method. The longer waste-factor essay is the tile guide. The tile category hub is the tool list.

Sources

  1. Daltile – FAQs (“What is Attic Stock?”) — accessed : “We highly recommend that you purchase approximately 10% more tile than you anticipate needing for your project.”
  2. CUSTOM Building Products – Polyblend Sanded Grout technical data sheet TDS-129 (PDF) — accessed : “Coverage for 25 lb bag: 12" x 12" x 3/8" tile, 1/8" joint – 348 ft² (32.3 m²); 3/16" – 234 ft²; 1/4" – 177 ft²”
  3. CUSTOM Building Products – VersaBond Professional Tile Mortar (coverage chart) — accessed : “Square foot coverage per 50 lb bag (min): 1/4" x 1/4" square-notch 90 sq. ft.; 1/4" x 3/8" 60; 1/2" x 1/2" 42; 3/4" x 9/16" U-notch @45° 34”
  4. Tile Council of North America – TCNA Handbook — general reference — not cited for a specific figure

Prefer manufacturer data sheets and published factors. Coverage, yield and waste vary by product — confirm the label you buy.

Looking for every tile tool in one list? See the Tile calculators category hub · Methodology · Updated