Grout Calculator
Enter your area, tile and joint size. See how much grout to buy.
100% in your browser - no upload, no sign-up.
Grout needed (approx.)
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Grout volume (exact)
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The weight is an estimate using a typical cementitious-grout density (~112 lb/ft³). Coverage varies by brand and mix - always check your grout bag's coverage chart before buying.
💡 Buy all bags at once - color varies between production lots.
⚠️ Use sanded grout past 1/8 in - unsanded cracks in wide joints.
How to use this grout calculator
- Enter your floor area in square feet, then your tile's length and width in inches.
- Set the joint (grout line) width and the joint depth - usually your tile's thickness - in inches.
- Read the approximate weight and the exact grout volume; a 10% waste allowance is included by default.
How the grout amount is calculated
Grout fills the gaps between tiles, so the amount depends on how much joint length there is per unit of floor. For a tile L×W inches, the grout volume per square foot of floor is ((L+W)/(L×W)) × jointWidth × jointDepth. Because the (L+W)/(L×W) term shrinks slowly as tiles get bigger, joint width has a bigger impact on grout use than tile size - doubling the joint width doubles the grout, while doubling the tile size barely changes it. The calculator multiplies that fraction by your floor area to get an exact volume in cubic inches and cubic feet. The weight is approximate: it converts volume to pounds using a typical cementitious-grout density of about 112 lb/ft³, and real coverage varies by brand and mix, so check your grout bag's coverage chart. A 10% waste allowance is added by default for mixing loss and spillage.
Frequently asked questions
- How much grout do I need?
- It depends on your floor area, tile size and joint dimensions. Enter all four above and the calculator returns an exact grout volume plus an approximate weight. As a rule of thumb, smaller tiles and wider or deeper joints need more grout. Buy a little extra and confirm the amount against the coverage chart on your grout bag.
- Does joint width change how much grout I need?
- Yes - more than tile size does. Grout volume is directly proportional to joint width and joint depth, so doubling the joint width doubles the grout. Tile size has a smaller effect: going from 12-inch to 24-inch tiles only modestly reduces grout, because the joint length per square foot falls slowly. When in doubt, measure your actual joint width.
- Why is the grout weight approximate - should I check the bag?
- The volume is exact geometry, but weight depends on the specific product. We convert volume to pounds using a typical cementitious-grout density of about 112 lb/ft³; sanded, unsanded and epoxy grouts differ, and the mixing water changes the final weight. Always confirm the amount against the coverage chart printed on your grout bag before buying.
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