Tile Calculator

This tile calculator estimates how many tiles, boxes, and material cost you need for any rectangular tiling project. Enter your measurements and tile specs to get a purchase-ready tile count with waste factored in.

1. Choose the project type. Select floor, wall, shower, backsplash, or other. The project type helps you apply the right measurement approach. For shower walls, measure each wall panel separately and add the areas. For backsplashes, measure from countertop to the bottom of upper cabinets.
2. Enter your area. Use "Room dimensions" if you know the length and width. Use "Known square footage" if you already calculated the area. For dimensions mode, you can add extra inches beyond whole feet for precision.
3. Enter tile length and tile width in inches. Check the actual dimensions on the product box. Nominal sizes like "12x24" can differ from the true face size by up to 1/16 inch. Using the actual dimension gives a more accurate tile count.
4. Set the grout gap. Enter the grout joint width in inches. Rectified (precision-cut) tiles use 1/16 in joints. Standard tiles use 1/8 in. Larger format tiles on floors often use 3/16 in. Enter 0 if you're using peel-and-stick tile with no grout.
5. Set the waste factor. Lowe's and Best Tile both recommend 10% extra for standard layouts. Use 15% for diagonal or herringbone patterns. Complex mosaic layouts with many cuts may need 20%.
6. Enter tiles per box and price (optional). Add the tiles per box count from the product label to see how many boxes to buy. Enter the price per tile, per box, or per sq ft to get an estimated material cost.
7. Click "Calculate tiles" to see your results.

Pro tip: Round up to full boxes and keep leftover tiles from the same batch for future repairs. Tile colors can vary between production runs, so matching a broken tile later from a different lot is risky. One extra box now costs far less than a second delivery or a mismatched repair.

Measurement tips by project type

• Floor: Measure the room at its widest points. Include closets and alcoves as separate rectangles and add the areas. Do not subtract small obstacles like toilet flanges or floor vents.
• Wall: Measure each wall panel width and height. Multiply to get the area of each section. Add all wall sections together.
• Shower: Measure each shower wall from the curb or tub lip to the top tile line. Include niche areas as extra surface. Shower walls often need 15% waste because of niche cuts, corners, and exposed edges.
• Backsplash: Measure from the countertop surface to the bottom edge of upper cabinets. Measure the width along the entire run, including behind the range. Most kitchen backsplashes are 15 to 18 inches tall.
• Bathroom floor and walls: Measure the bathroom floor separately from the shower enclosure. For bathroom wall tile around a vanity or tub surround, measure each wall panel and subtract the mirror or window area only if it's larger than 4 sq ft.

Assumptions and limitations

This tile calculator assumes rectangular areas. L-shaped rooms, curved walls, and diagonal cuts require splitting the project into multiple rectangles. The calculator does not account for tile layout pattern waste beyond the percentage you enter. Herringbone, chevron, and pinwheel patterns generate more cut waste than a straight grid.

Cost estimates use the price basis you select. Actual costs vary by retailer, region, and tile material. Ceramic tile typically costs $1 to $5 per sq ft, porcelain runs $3 to $10, and natural stone can exceed $15 per sq ft (2026 prices).

This tile calculator converts your project dimensions and tile specs into a purchase-ready tile count. Here's how the tile calculation works step by step.

Finding your project area

Multiply the project length by its width to get total square footage. A 10 ft by 12 ft kitchen floor is 10 × 12 = 120 sq ft. If you already know your total area, enter it directly in "Known square footage" mode.

Calculating tile coverage

Each tile covers a specific area based on its face dimensions. Common sizes and their coverage: 12 × 12 in (1 sq ft), 6 × 24 in (1 sq ft), 12 × 24 in (2 sq ft), 18 × 18 in (2.25 sq ft), and 3 × 6 in subway tile (0.125 sq ft). When you add a grout gap, the effective tile footprint grows slightly because each tile occupies its face area plus half the grout joint on each side. A 1/8 in grout gap changes a 12 × 24 in tile's effective footprint to 12.125 × 24.125 in.

Tile count and waste

Divide the project area by one tile's effective coverage, then round up to get the base tile count. Multiply by the waste factor (1 + waste % / 100), and round up again. Rounding up is critical because you can't buy a fraction of a tile.

Worked example

A 10 ft × 12 ft floor using 12 in × 24 in tile with 1/8 in grout gap and 10% waste:

• Project area = 10 × 12 = 120 sq ft
• Effective tile size = 12.125 in × 24.125 in = 1.01 ft × 2.01 ft = 2.03 sq ft
• Base tiles = ceiling(120 / 2.03) = 60 tiles
• With 10% waste = ceiling(60 × 1.10) = 66 tiles
• If 8 tiles per box: ceiling(66 / 8) = 9 boxes (72 tiles total)

The 6 extra tiles from waste and the 6 extra from box rounding give you 12 spare tiles. Keep them for future repairs from the same batch.

Common gotchas

• Nominal vs. actual tile size: A tile labeled "12×24" may measure 11-7/8 × 23-7/8 inches. Always check the actual size on the product box.
• Don't subtract small openings: Toilet flanges, floor registers, and outlet cutouts don't save tiles because the surrounding cuts consume just as much material.
• Pattern layouts use more tile: A diagonal (45°) layout adds about 15% waste. Herringbone and chevron patterns add 15% to 20%. Mosaic tile sheets with irregular cuts can add 10% to 15%. Adjust the waste factor accordingly.
• Box rounding adds overage: If your box size doesn't divide evenly into the tile count, you'll buy extra tiles. Keep them as matching spares.