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Grout Calculator

Estimate grout needed for any tile project with bag count, cure time, and coverage based on tile size, joint width, and area. Free.

Frequently Asked Questions

How much grout do I need?

Grout coverage depends on tile size, joint width, and joint depth. As a rough guide, a 25 lb bag covers about 100–150 sq ft of 12"×12" tile with 1/8" joints, or only 30–50 sq ft of 12"×24" tile with 1/4" joints. Always check the bag's coverage chart - they vary by brand.

What is the difference between sanded and unsanded grout?

Sanded grout contains fine sand for strength and is required for joints 1/8" or wider. Unsanded grout is smoother and used for joints 1/16" to 1/8" and on polished stone or glass tile (sand can scratch them). Epoxy grout is stain-proof and waterproof but harder to install.

How long does grout take to cure?

Initial set: 24 hours before light foot traffic. Full cure for water exposure: 72 hours minimum, 7 days for shower use. Sealing is recommended after a 48–72 hour cure for cement-based grout. Epoxy grout reaches full chemical cure in about 24 hours and does not need sealing.

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Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

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How This Calculator Works

Enter tile dimensions (length × width in inches), grout joint width (typically 1/8" to 1/2"), and total area to be grouted (in sq ft). The calculator estimates grout needed using a simplified volume formula based on the joint width and tile size. Grout density varies by type (unsanded, sanded, epoxy). The result includes a 10% waste factor and bag count (standard bags: 25 lbs). Actual consumption varies with application method, tile porosity, and installer experience.

Grout vs. Caulk

Grout

Rigid, cementitious: hardens like concrete.
Use for: joint lines between tiles on walls, floors, countertops.
Weakness: cracks if substrate shifts; not flexible.
Waterproofing: moderately water-resistant; requires sealing (unsanded and sanded grouts).

Caulk

Flexible, silicone or urethane: remains slightly rubbery.
Use for: expansion joints, corners, edges where movement is expected.
Advantage: absorbs movement; won't crack.
Waterproofing: excellent water resistance; ideal for bathrooms and showers.

Best practice: use grout for field tiles and caulk for perimeter/corners to allow for expansion/contraction.

Sanded vs. Unsanded Grout

Unsanded Grout

Joint width: up to 1/8"
Advantages: smoother finish, no sand migration, easier to clean.
Disadvantages: weaker, shrinks more, more prone to cracking.
Use: small or narrow joints, polished/delicate tiles, walls.

Sanded Grout

Joint width: 1/8" to 1/2"+
Advantages: stronger, less shrinkage, more durable.
Disadvantages: can scratch polished tiles, slightly more difficult to clean initially.
Use: larger joints, floors, areas with heavy traffic.

Epoxy Grout

Performance: superior water resistance, stain resistance, durability.
Advantages: ideal for pools, kitchens, high-moisture areas; does not require sealing.
Disadvantages: difficult to work with, harder to clean, more expensive.
Cost: 3–5× cost of cement grout.

Color and Maintenance

Grout comes in many colors; select one that complements your tiles. Light-colored grout shows dirt and staining; dark grout hides imperfections. Sealed grout resists staining and water infiltration. Typical sealing: apply liquid sealer 72 hours after grout cures; reapply every 1–3 years. Unsealed grout requires sealing, especially in kitchens and bathrooms.

Removing Old Grout

Old, cracked, or discolored grout must be removed before re-grouting. Tools: grout saw (manual or oscillating), grout removal blade for drill, or rotary tool. Remove grout to at least 1/4" depth. Vacuum out dust. Common project: re-grouting a bathroom takes 1–3 days (removal, prep, new grout, sealing).

Open Time and Cure

Open time: how long you can work and adjust tiles. Unsanded/sanded grouts: 10–15 min in normal conditions. Epoxy: 30–45 min (advantage: longer working time). Cure time: before you can grout, seal, or use the surface. Cement grout: 24–48 hours. Epoxy: 72–96 hours. Don't walk on floors or expose to water during cure.

Common Mistakes

Using unsanded grout for wide joints (>1/8") → cracks.
Mixing too much water → weak, shrinking grout.
Not wiping joints during initial set → excess grout hardens and is hard to remove.
Grouting too early → tiles may shift; let thinset fully cure first.
Skipping sealing → stains and mold growth.