Grout Calculator

Tell it your tile size, joint width and depth, and the area — and it estimates how many pounds of grout to buy before you tile.

📖 How it works & FAQ

Tile length (in)

Tile width (in)

Joint width (in) 1/16"=.0625 · 1/8"=.125 · 1/4"=.25

Joint depth (in) Usually the tile thickness

Area to tile (sq ft)

— Grout needed pounds

— Buy this much includes 10% waste

— Coverage sq ft per pound

How much grout will you actually need?

Grout fills the joints between your tiles, so the amount you need depends on four things: how big each tile is, how wide the joints are, how deep they run, and how much floor or wall you are covering. Small tiles and wide joints eat far more grout than large-format tiles with tight seams. This calculator uses the standard tile-industry coverage formula — lbs = ((tile length + tile width) ÷ (tile length × tile width)) × joint width × joint depth × area × constant — to turn those four numbers into a realistic weight in pounds before you head to the store.

Why joint depth matters as much as width

It is easy to remember joint width and forget depth, but they multiply together. A 1/8" joint that runs a full 3/8" deep holds three times the grout of one that is only 1/8" deep. As a rule of thumb, joint depth roughly equals your tile thickness, so measure a spare tile if you are unsure. Getting depth right is the difference between one bag and two.

How to use it

Enter your tile length and width in inches (for a 12" square tile, use 12 and 12).
Type your joint width — the hint lists the common fractions as decimals.
Set joint depth, which is usually your tile thickness.
Enter the total area you are tiling in square feet.
Read the pounds needed, the buy-this-much figure with 10% waste built in, and the coverage per pound.

These are estimates, not professional advice — always check the manufacturer's coverage chart on the bag and buy a little extra so every batch matches.

FAQ

How much extra grout should I buy?: Add at least 10% for waste, spills, and mixing leftovers — the "buy this much" result already includes it. Round up to whole bags.
What joint width should I use?: Rectified large tiles often use 1/16" to 1/8"; standard tiles use 1/8" to 3/16"; and rustic or handmade tiles may need 1/4" or more.
Does tile size really change the amount?: Yes, a lot. Smaller tiles create more joints per square foot, so mosaics and 4" tiles use several times the grout of 24" format tiles.
Sanded or unsanded — does it affect the weight?: Coverage is similar, but sanded grout suits joints 1/8" and wider while unsanded suits narrow joints. This tool estimates weight, not grout type.