How grout quantity is calculated
This calculator uses the TCNA (Tile Council of North America) industry-standard method for estimating grout. The formula calculates the total volume of grout joints in your installation and converts it to weight using the density of your chosen grout type.
The TCNA grout formula
The key insight is the perimeter ratio: smaller tiles have more grout joints per square foot than larger tiles. A 4×4 tile installation has dramatically more joint length than a 24×24 installation covering the same area.
The formula multiplies: joint length per square inch of tile × joint width × tile depth × grout density × total area. The result is grout weight in pounds.
Grout density by type
- Sanded grout (0.1875 lb/in³) — Standard for joints 1/8" and wider. The sand aggregate provides strength for wider joints.
- Unsanded grout (0.165 lb/in³) — For joints narrower than 1/8". Smoother texture, slightly less dense.
- Epoxy grout (0.22 lb/in³) — For wet areas, commercial kitchens, and high-traffic zones. More expensive but nearly impervious to staining and moisture.
When to use each grout type
Sanded: Most floor tile, most wall tile with joints ≥1/8". The sand prevents cracking in wider joints.
Unsanded: Polished marble (sand scratches the surface), rectified tile with narrow joints, glass mosaic.
Epoxy: Showers, pools, restaurant kitchens, hospitals. Higher cost, harder to work with, but superior durability and stain resistance.