How to use this calculator
Start by entering the dimensions of the area you plan to tile in square feet. Then input your tile size (length and width in inches), tile thickness, and the desired grout joint width. The calculator uses these measurements to determine the total volume of grout joints across your project.
Choose your grout type (sanded, unsanded, or epoxy) and the calculator will convert the joint volume into pounds and bags needed. You can adjust the waste factor to account for variations in joint depth and application technique.
Understanding grout coverage
Grout coverage depends on four key variables: tile size, joint width, tile thickness, and grout density. Smaller tiles create more grout lines per square foot, so mosaic tiles use significantly more grout than large format tiles covering the same area.
Joint width has a major impact on grout quantity. Doubling the joint width from 1/8 inch to 1/4 inch roughly doubles the amount of grout needed. Tile thickness also matters because deeper joints require more material to fill completely.
The standard formula multiplies the total linear length of grout joints by the joint cross section area, then divides by the grout density to convert from volume to weight. This calculator handles all of that math automatically.
Frequently asked questions
How much grout do I need per square foot of tile?
The amount varies based on tile size, joint width, and tile thickness. As a general reference, 12x12 inch tiles with 1/8 inch joints need about 0.7 pounds per square foot. Smaller mosaic tiles (1x1 or 2x2 inch) can need 2 to 3 pounds per square foot because of the many grout lines. Enter your specific dimensions above for an accurate estimate.
What is the difference between sanded and unsanded grout?
Sanded grout contains fine sand particles and is meant for joints wider than 1/8 inch. The sand adds structural strength and resists shrinkage in wider gaps. Unsanded grout is smoother and is used for joints 1/8 inch and narrower, especially with polished stone or glass tiles that could be scratched by sand particles.
How long does tile grout take to dry?
Most cement based grouts are firm enough for light foot traffic within 24 hours. Full curing takes 48 to 72 hours, during which you should avoid heavy traffic, water exposure, and applying sealer. Temperature and humidity affect curing time, so allow extra time in cold or damp conditions.
Should I seal my tile grout?
Yes, cement based grout should always be sealed to protect against stains and moisture. Apply a penetrating sealer after the grout has fully cured (48 to 72 hours). Reapply every 1 to 2 years in wet areas like showers and kitchen backsplashes. Epoxy grout does not need sealing because it is naturally waterproof and stain resistant.