Calculate tile grout volume, packages and cost
Use the tile dimensions to estimate joint volume, then enter the coverage printed for your grout product to calculate whole packages.
Enter measurements and select Calculate.
Use the coverage stated for the same tile size, joint width and joint depth whenever the product data sheet provides it. Decimal point or comma accepted; omit thousands separators.
How to use this grout calculator
- Choose US or metric units and enter the total tiled surface.
- Enter actual tile length and width plus the finished joint width and depth.
- Set an allowance for waste, site variation and material left in the bucket.
- Copy the package coverage from the manufacturer's current label or data sheet for comparable joint dimensions.
- Enter an optional package price. The calculator rounds purchasing quantities up to whole packages.
Grout calculation formula
For a repeating rectangular grid, joint share = 1 − (tile length × tile width) ÷ ((tile length + joint width) × (tile width + joint width)). Theoretical grout volume = tiled area × joint share × joint depth. Volume with allowance = theoretical volume × (1 + allowance ÷ 100). Packages = area with allowance ÷ package coverage, rounded up.
This geometric model accounts for the crossing of horizontal and vertical joints once. It assumes uniform rectangular tiles, consistent spacing and full-depth joints.
Worked example
For 100 ft² of 12 × 12 in tile, 1/8 in joints and 3/8 in joint depth, the joint share is about 2.051%. The theoretical joint volume is about 1.815 L. With 10% extra, the volume is about 1.997 L and the purchasing area is 110 ft². At 25 ft² per package, purchase 5 packages.
Six calculated examples
| Tiled area | Volume with allowance | Packages at 25 ft² each |
|---|---|---|
| 25 ft² | 0.499 L | 2 |
| 50 ft² | 0.998 L | 3 |
| 75 ft² | 1.497 L | 4 |
| 100 ft² | 1.997 L | 5 |
| 150 ft² | 2.995 L | 7 |
| 200 ft² | 3.993 L | 9 |
Coverage and limitations
Grout density, aggregate, mixing water, tile-edge shape, joint profile and application loss vary by product and installation. The geometric liters are an estimate, not a substitute for the product's coverage chart. Package calculations use the coverage you enter, so match its units and conditions. This tool is for tile joints; it does not estimate structural grout, concrete masonry unit fill, epoxy resin ratios or paving-joint compounds.
Frequently asked questions
Should I use nominal or actual tile size?
Use the actual face dimensions that repeat across the installed grid. Nominal sizes can differ from measured sizes.
Does wider grout use more material?
Yes. Wider or deeper joints increase volume. Smaller tiles also create more joint length across the same surface.
Why does the package estimate use coverage instead of liters?
Manufacturers sell products with different densities and formulations. Coverage from the specific product is usually a safer purchasing basis than converting theoretical volume to weight.