Tile & Grout Weight Volume Calculator
Calculate floor and wall tile box counts, grout dry weight in pounds/kg, and thinset mortar bags with TCNA joint formula and waste allowance.
Tile & Grout Project Details
Installation Material Takeoff
TCNA Joint & Grout Selection Rules
About this tool
How to use it
- Choose your measurement system (US Customary in feet/inches/lbs or Metric in meters/mm/kg).
- Enter your room or wall length and width to establish net square footage or square meters.
- Select your tile format (12x12, 12x24, 24x24, 6x24 plank, subway, mosaic), tile thickness, and grout joint spacing width.
- Choose your installation pattern waste allowance (10% standard, 15% diagonal, 20% herringbone) and box coverage to get exact box counts, grout bag purchases, and thinset mortar quantities.
Why it matters
Running out of tile mid-installation risks mismatched dye lots and delayed tiling jobs, while guessing grout quantities leads to either excessive waste or rushed store trips with drying thinset. This calculator applies the Tile Council of North America (TCNA) grout joint volumetric formula and pattern waste factors to give an accurate, full-materials takeoff.
When to use it
Use this tool before ordering materials from tile distributors or home improvement centers, estimating job material costs for contracting bids, or determining whether sanded, unsanded, or epoxy grout is required for your joint width.
Good to know
Grout dry weight calculations use the TCNA volumetric formula: Weight = [(Length + Width) * Thickness * Joint Width * Area * Density] / (Length * Width), with a 10% scrap/washout allowance included. Always check the packaging label of your specific tile manufacturer, as actual carton square footage varies (commonly 10 to 18 sq ft per box).
Common questions
Should I use sanded or unsanded grout?
Use unsanded grout for grout joints narrower than 1/8 inch (such as rectified porcelain, polished marble, or delicate glass tiles) to avoid scratching the tile surface. Use sanded grout for joints 1/8 inch to 1/2 inch wide; the sand aggregate provides structural strength and prevents the grout from shrinking and cracking as it cures.
How much tile waste should I calculate for my project?
Plan for 10% extra for standard straight or grid layouts, 15% for diagonal installations or large format tiles (12x24 and larger) that require more perimeter cutting, and 20% for herringbone patterns, intricate mosaic niches, or rooms with numerous obstacles.
How many bags of thinset mortar do I need for tiling?
A standard 50-pound bag of polymer-modified thinset mortar covers approximately 80 to 90 square feet when using a 1/4" x 1/4" square-notch trowel for standard tiles up to 12" x 12". For large format tiles requiring a 1/2" x 1/2" trowel or medium-bed mortar, one 50-pound bag covers approximately 40 to 50 square feet.
Why is grout coverage lower for smaller tiles?
Smaller tiles (such as 3" x 6" subway tiles or 2" x 2" mosaics) have far more linear feet of grout joints per square foot of floor area than large format tiles. A 100 sq ft room tiled with 2x2 mosaics requires roughly six times more grout than the same room tiled with 12x12 tiles at the same joint width.
How do you calculate the number of tile boxes needed?
Multiply your room's net square footage by your waste multiplier (e.g. 1.10 for 10% waste) to find gross square footage, then divide by the square foot coverage per carton printed on the box and round up to the next whole carton. For a 120 sq ft room with 10% waste (132 sq ft gross) and 15 sq ft per box, you need 132 ÷ 15 = 8.8, rounded up to 9 boxes.