Grout Calculator

Joint volume from tile and gap geometry → bags with waste. Click any i for detail.

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Tile & joints

Area (sq ft)
i
Area

Total tiled area.

Tile width (in)
i
Tile W

Nominal tile width.

Tile height (in)
i
Tile H

Nominal tile height.

Joint width (in)
i
Joint W

Grout gap.

Joint depth (in)
i
Joint D

Often ~ tile thickness.

Bag size (lb)
i
Bag

Typical 25 lb bag.

Waste (%)
i
Waste

Contingency for mixing loss.

How to use this calculator

  1. Enter tiled area and tile size.
  2. Set joint width and depth.
  3. Choose bag size and waste %.
  4. Read volume and bags (rounded up).

Results explained

Grout volume is approximated from joint cross-section relative to each tile’s footprint, scaled by area. Density defaults assume a sanded-ish mix (~100 lb/cu ft) — check your product’s coverage chart.

Quick reference: grout volume

factor ≈ ((W+H)×jw×jd)/(W×H); scale by area.

ItemDetail
Narrow jointsLess grout
Thicker tileDeeper joints → more
Waste 10%Common buffer
Label coverageOverrides this sketch

Confirm bag yield on the product label before buying.

How the estimate is built

cu_in = area×144×factor; lbs ≈ cu_ft×100; bags = ceil(lbs×(1+waste%)/bag).

Example scenario

100 sq ft of 12×12 with 1/8×1/4 joints → roughly a couple of 25 lb bags with waste.

FAQ

Sanded vs unsanded?

Density/coverage differs — prefer the bag chart.

Mosaic sheets?

Use the sheet’s effective tile size or manufacturer coverage.

Wall vs floor?

Same geometry; product choice differs.

Thinset too?

See the thinset calculator.