From measured space to purchasable material
Tile dimensions and the spaces between tiles both affect how many pieces cover a surface. This quantity estimator treats each tile plus one grout joint as a repeating module, applies a cutting and breakage allowance, and rounds the final order to the box size. It is a useful broad estimate for rectangular floor or wall tiles. Edge cuts, centered borders, diagonal layouts, and patterns can change the usable yield. Use the tile layout calculator when you need to inspect how full rows and columns fit an actual rectangular surface.
Measure, select yield and round the order
- Measure the actual tiled area, excluding sections outside the installation.
- Use actual tile dimensions and the planned grout joint width.
- Enter the package tile count and check the box-rounded order against the installation layout.
Net requirement and purchase calculation
A worked example
For 120 sq ft using 12 × 12 inch tiles and 1/8-inch joints, the module estimate is about 117.54 tiles. With 10% extra, order 130 tiles, or 13 boxes of ten.
Tile Quantity: what changes the result?
Separate installed coverage from the material you can purchase. The comparisons below are calculated from this page’s default example. Each row changes only the named input; all other inputs stay at their displayed example values. These are mathematical scenarios, not measurements from a completed project.
| Changed assumption | Default input | Comparison input | Result: default → comparison |
|---|---|---|---|
| Surface area | 120 sq ft | 144 sq ft | Boxes to buy: 13 → 16 Tiles including allowance: 130 → 156 |
| Tile length | 12 in | 14.4 in | Boxes to buy: 13 → 11 Tiles including allowance: 130 → 108 |
| Tile width | 12 in | 14.4 in | Boxes to buy: 13 → 11 Tiles including allowance: 130 → 108 |
| Grout joint width | 0.125 in | 0.15 in | Tiles including allowance: 130 → 129 |
Displayed values are rounded. Whole-pack results change in steps; continuous quantities may change before a new pack is needed. To compare your actual project, enter your dimensions above, save a scenario, then change one assumption.
Coverage, allowance and purchasing limits
- The repeating-module approximation distributes joints across the whole surface; perimeter joints and cut borders are not individually modeled.
- Nominal tile sizes can differ from actual dimensions. Use the specification for the product being ordered.
- Decorative inserts and mixed-size tile patterns need a separate piece schedule.
Frequently asked questions
How many 12 by 12 tiles cover 120 square feet?
With a 1/8-inch joint and 10% allowance, this approximation gives 130 tiles; ten-tile boxes mean buying 13 boxes.
Does this calculate diagonal tile cuts?
It applies your chosen waste percentage but does not optimize diagonal cuts. Increase the allowance based on a drawn layout.
Does the result include adhesive and grout?
No. Use the thinset and grout tools with the same installed surface area.
Read the project guides
- Tile Layout, Border Cuts, and Waste: Why Area Alone Is Not Enough
Compare tile-and-joint area estimates with centered grid positions, border cuts, source tiles, offcut reuse, and box rounding.
- Grout vs Thinset Quantity: Joint Volume, Trowel Coverage, and Bag Rounding
Calculate grout and tile mortar separately using joint geometry, product coverage ranges, back-buttering, and independent bag quantities.
Calculation method: JICWH methodology. Examples are planning assumptions, not product recommendations.