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Grout Calculator
Estimate grout weight from tiled area, tile size, joint width, joint depth, and waste allowance.
Enter your dimensions
Current unit: feet. The estimate updates automatically in your browser.
Enter the total area to be grouted.
Enter the tile length.
Enter the tile width.
Enter the grout joint width.
Enter the joint depth to be filled.
Optional extra allowance for cleanup, uneven joints, and ordering margin.
Estimated result
Grout needed
Enter your inputs
Your estimate will appear here automatically once the required inputs are valid.
Guide
How to use this estimate
How the grout calculator works
This calculator estimates the volume of grout joints across the tiled area, then converts that volume into grout weight using an assumed cementitious grout density of 1.6 g/cm³, equal to 1600 kg/m³.
The result is shown by weight because grout is usually bought by weight. Imperial mode shows pounds first and kilograms as the equivalent value. Metric mode shows kilograms first and pounds as the equivalent value.
What to measure
Measure the total tiled area. Then enter tile length, tile width, joint width, and joint depth. In imperial mode, tile and joint dimensions are entered in inches. In metric mode, they are entered in millimeters.
Joint depth is usually related to the tile thickness and how much of the joint needs filling. For exact purchasing, compare this estimate with the grout manufacturer's coverage chart.
Example grout calculation
- Tiled area: 120 square feet
- Tile size: 12 inches × 12 inches
- Joint width: 1/8 inch
- Joint depth: 1/4 inch
- Waste allowance: 10%
- Assumed grout density: 1.6 g/cm³
Estimated grout needed: about 5.72 pounds, equivalent to about 2.60 kilograms.
Quick reference
| Item | Value | Note |
|---|---|---|
| Joint volume | Area × joint factor | Smaller tiles and wider joints need more grout. |
| Density assumption | 1.6 g/cm³ | Used to convert joint volume into grout weight. |
| Best check | Manufacturer chart | Final coverage varies by grout type and product. |
Common mistakes to avoid
- Using tile area without entering the tile dimensions.
- Entering joint width in millimeters while the calculator is set to imperial.
- Assuming grout coverage is identical across all grout products.
Frequently asked questions
Why does tile size affect grout quantity?
Smaller tiles create more grout line length across the same area, so they usually need more grout than large-format tiles.
Is the grout density exact?
No. The calculator uses an assumed cementitious grout density of 1.6 g/cm³ for planning. Actual density and coverage can vary by grout type, additives, joint shape, tile surface, and manufacturer.
Should I still check the grout bag?
Yes. Use this as a planning estimate, then compare it with the product coverage chart before buying.