Grout Calculator
Calculate exactly how much grout you need for your tile project. Accounts for tile size, joint width, tile thickness, and waste.
Area to Grout
Tile Dimensions
Standard tile is 1/4" (0.25") thick
Grout Joint Width
1/8" is most common for floor tiles
Your Results Will Appear Here
Enter your tile area, tile dimensions, and joint width, then click “Calculate” to see how much grout you need.
Top-Rated Grout & Grouting Tools
Hand-picked products to help you get the best results on your project.
Mapei
Mapei Keracolor U Unsanded Grout, 10 lbs, Avalanche White
- ✓Unsanded formula
- ✓Polymer modified
- ✓Consistent color
Custom
Custom Building Products Polyblend Plus Sanded Grout, 25 lbs
- ✓Sanded for wide joints
- ✓Stain resistant
- ✓25 lb bag
Red Devil
Red Devil Pre-Mixed Tile Grout Squeeze Tube, 5.5 oz
- ✓Pre-mixed
- ✓Squeeze tube
- ✓Great for small repairs
QEP
QEP Grout Float with Soft-Grip Handle, 9 x 4 Inch
- ✓Rubber pad
- ✓Soft-grip handle
- ✓Professional quality
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How to Use This Grout Calculator
Step 1: Enter Your Area
Enter the total square footage of the area you’re grouting. For multiple rooms, add the areas together or calculate them separately.
Step 2: Enter Tile Dimensions
Enter your tile’s length, width, and thickness in inches. Standard floor tile is 1/4" thick. Larger tiles need less grout per square foot.
Step 3: Select Joint Width
Choose your grout joint width. 1/8" is standard for floor tiles. Wider joints need more grout. Use 1/16" for rectified (precision-cut) tiles.
Step 4: Get Your Results
Click Calculate to see total pounds needed, bag quantities (10-lb and 25-lb), and estimated cost range for your project.
Step 5: Choose Your Bags
Buy either 10-lb bags for small projects or 25-lb bags for better value on larger projects. Both estimates are provided for your convenience.
Understanding Grout Types & Usage
Sanded vs. Unsanded Grout
| Feature | Unsanded Grout | Sanded Grout |
|---|---|---|
| Joint Width | ≤ 1/8" | > 1/8" |
| Texture | Smooth, paste-like | Gritty, thicker |
| Best For | Walls, small joints, polished stone | Floors, wide joints, outdoor |
| Shrinkage | More shrinkage in wide joints | Minimal shrinkage |
How Tile Size Affects Grout Usage
Smaller tiles have more joint length per square foot, requiring significantly more grout. A floor covered in 2"×2" mosaic tiles needs 4–6 times more grout than the same floor with 12"×12" tiles. Tile thickness also matters — thicker tiles mean deeper joints that hold more grout.
Grout Sealing
Most cement-based grout should be sealed 24–72 hours after installation to prevent staining and moisture penetration. Epoxy grout is the exception—it doesn’t need sealing. Reapply grout sealer every 1–2 years in wet areas (bathrooms, kitchens) and every 3–5 years in dry areas.
Pro Tips for Grouting
Use Unsanded Grout for Joints 1/8 Inch or Smaller
Unsanded grout flows into narrow joints more easily and produces a smoother finish. Using sanded grout in narrow joints makes it harder to pack properly and can scratch polished tile surfaces like marble or glass.
Mix Grout to Peanut Butter Consistency
Too wet and the grout will be weak and shrink as it dries. Too dry and it won’t pack into joints properly. The ideal consistency is like smooth peanut butter—firm enough to hold its shape but soft enough to push into joints easily.
Work in Small Sections
Grout starts setting within 15–20 minutes. Only mix enough grout for about 10–15 minutes of work at a time. Spread grout over a 3–4 square foot area, pack it into joints, then clean the surface before moving to the next section.
Clean Excess Within 15–20 Minutes
Use a damp (not wet) sponge to wipe excess grout from tile surfaces before it hardens. If you wait too long, you’ll need a grout haze remover. Rinse your sponge frequently and use diagonal strokes across joints to avoid pulling grout out.
Seal Grout After 24–48 Hours
Once grout has cured for at least 24 hours (72 hours in wet areas), apply a penetrating grout sealer. This prevents stains from absorbing into the porous grout surface. Reapply sealer annually in bathrooms and kitchens.
Frequently Asked Questions
It depends on tile size, thickness and joint width. For 100 sq ft of 12”×12” tile with 1/8” joints, plan on about 6 lbs of grout if the tile is 1/4” thick and about 9 lbs if it’s 3/8” thick (including 10% extra). Smaller tiles (like mosaics) or wider joints need significantly more grout. Our calculator gives you an accurate estimate based on your specific tile and joint dimensions.
Use unsanded grout for joints 1/8 inch (3mm) or smaller—it’s smoother and easier to push into thin joints. Use sanded grout for joints wider than 1/8 inch—the sand provides strength and prevents cracking in wider gaps. For natural stone tiles, use unsanded grout regardless of joint size to avoid scratching polished surfaces.
Grout typically takes 24–72 hours to fully cure before you can seal it or expose it to water. Initial set happens in about 15–30 minutes (when you should clean excess from tile surfaces). Avoid walking on freshly grouted floors for at least 24 hours. Full strength develops over about a week.
Yes, you can repair or add grout later, but color matching can be tricky. Grout color changes as it dries and cures, so a new application next to old grout may look slightly different. For best results, use the exact same brand and color, and consider regrouting the entire area for a consistent look.
Common causes include too much water in the grout mix (making it weak), movement or flex in the substrate (especially on wood subfloors), grout joints that are too thin for the tile type, or the grout drying too quickly. Use a flexible (polymer-modified) grout in areas prone to movement, and follow mixing instructions carefully.
Mosaic tiles have much more joint area relative to tile area, so they need 2–4 times more grout per square foot than large tiles. Enter the individual tile size (e.g., 1”×1” or 2”×2”) into our calculator, and it will account for the higher number of joints automatically.