Interior & Finishes

Grout Calculator

This grout calculator estimates the grout volume and pounds for a tiled area; our flooring installation guide covers tile layout and joints. Grout fills the joints between tiles, so the amount depends on how much joint there is: small tiles and wide joints use far more grout than large tiles with tight joints. This calculator computes the joint volume exactly, then converts it to pounds using a density you can edit.

Grout products differ. The default density (100 lb per cubic foot) is an approximation — your grout manufacturer's coverage chart is the authority, so compare the result with it before buying.

Results from this grout calculator are planning estimates; confirm quantities and prices with your supplier or contractor before you order.

Your results will appear here

Enter your measurements and press Calculate. Defaults show a typical example.

How to use the grout calculator

Enter the tiled area.
Enter tile length, width and thickness (the joint depth).
Enter the joint width you will use.
Compare the result with your grout's coverage chart and adjust the density if needed.

Formula

Joint fraction = (L + W) × J ÷ (L × W). Grout volume = area × 144 × joint fraction × depth (in³) ÷ 1,728 (ft³). Weight = volume × density × (1 + waste).

Worked example

100 sq ft of 12 × 12 × ⅜ in tile with 1/8 in joints: 2.08% of the surface is joint, about 112.5 in³ (0.065 ft³) of grout — roughly 7 lb at the default density with 10% waste.

Tips for using the grout calculator

Joint depth is usually the tile thickness; thicker tiles use more grout.
Mix grout in small batches so it does not set before you finish the area.
Use sanded grout for wider joints and unsanded grout for very narrow joints.