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Calculation Machine

Grout Calculator

Pounds of grout for any tile size, joint width and area.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
Grout needed
11.72 lb
Bags to buy
2 x 10 lb
Coverage rate
0.098 lb per sq ft
With 10% waste
12.89 lb

Working

  1. 1((12+12)/(12x12)) x 0.125 x 0.375 x 12.5 = 0.098 lb/ft2

Quick answer

Grout volume depends on tile size, joint width and depth. Smaller tiles and wider joints need far more grout per square foot.

The formula

lb/ft2 = (L+W)/(L x W) x joint x thickness x 12.5

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Tile length12 in
  • Tile width12 in
  • Tile thickness0.375 in
  • Joint width0.125 in
  • Area to tile120 sq ft
  • Bag size10 lb

Result

  • Grout needed11.72 lb
  • Bags to buy2 x 10 lb
  • Coverage rate0.098 lb per sq ft
  • With 10% waste12.89 lb

How to use the Grout Calculator

  1. 1Enter the real tile dimensions and thickness from the box.
  2. 2Set the joint width you plan to use with your spacers.
  3. 3Buy 10% extra so you can mix a consistent colour throughout.

Frequently asked questions

Sanded or unsanded grout?

Sanded for joints 1/8 inch and wider; unsanded for narrower joints and polished stone that sand would scratch.

Why does mosaic tile use so much grout?

Grout volume scales with the total joint length per square foot. Small tiles have far more joint per area, sometimes five times as much as large format.

About this calculator