Tile Calculator
Calculate how many tiles you need for a floor or wall area, including waste and grout gap adjustments.
Area Dimensions
Tile Options
Default: 1/8" (0.125")
Last updated: April 7, 2026· Reviewed by the CalcNeeds Team
About This Calculator
This tile calculatortells you exactly how many tiles you need to cover a floor, wall, backsplash, or shower surround. Enter the area dimensions and your tile size, and the tool accounts for grout gaps, waste, and layout pattern to produce a realistic estimate of tiles, boxes, and total square footage. Whether you're tiling a small bathroom or a 1,000 sq ft kitchen, this calculator saves you a return trip to the store.
It supports every common tile size — from small 4×4 mosaics to large-format 24×24 squares and modern 12×24 plank tiles — plus a custom option for any unusual size. Grout gap, waste percentage, and diagonal layout adjustments are all built in.
How to calculate how many tiles you need
The basic formula is simple: (room area in sq ft × 144) ÷ (tile width in inches × tile height in inches) = number of tiles. Then add a waste factor of 10–15% on top to cover cuts and breakage. So a 100 sq ft room being tiled with 12×12 tiles is (100 × 144) ÷ (12 × 12) = 100 tiles, plus 10–15% waste = 110–115 tiles.
For larger or smaller tiles the math is the same — replace 12×12 with your actual tile dimensions. The calculator above also factors in grout gap, which slightly reduces the tile count because the grout takes up some of the area.
Choosing the right waste factor
10% — simple rectangular rooms, straight grid pattern, no obstacles. The bare minimum.
15% — rooms with many cuts around toilets, vanities, kitchen islands, doorways, and pipes.
20% — diagonal layouts, herringbone or chevron patterns, fragile natural stone, or your first DIY tile project where mistakes are likely.
Diagonal patterns produce more unusable offcuts because every edge cut is at 45°. The calculator above adds an extra 15% automatically when you select the diagonal layout option.
Common tile sizes and where to use them
4×4 and 6×6 inches: classic small tiles for bathroom walls, backsplashes, and decorative borders. Easy to cut, lots of grout lines.
12×12 inches: the workhorse standard for bathroom and kitchen floors. Easy to install and widely available.
18×18 and 24×24 inches: large-format tiles that make small rooms look bigger and reduce grout lines. Heavier and harder to cut, often need a wet saw.
6×24 and 12×24 inches: plank-style tiles designed to look like wood. Popular in modern kitchens, baths, and living rooms. Best installed in a 1/3 offset, not a half offset, to avoid lippage.
2×2 mosaics on a 12×12 sheet: small mosaics pre-mounted on mesh sheets. Calculate by sheet rather than by individual tile.
Grout gaps and grout coverage
Grout gap width affects the look of the finished floor and the amount of grout you need. 1/16" is the thinnest practical gap and is mostly used with rectified tiles. 1/8" is the standard for most ceramic and porcelain installations. 3/16" to 1/4" is common for natural stone and rustic looks. Wider grout gaps mean slightly fewer tiles but more grout material.
Frequently Asked Questions
How do I calculate how many tiles I need?
Multiply the room's square footage by 144 (to convert to square inches), then divide by the tile size in square inches. A 100 sq ft room with 12×12 tiles needs 100 tiles. Add 10–15% for waste. The calculator above does this automatically.
How much waste should I add for tile?
10% for simple rectangular rooms, 15% for rooms with many cuts (around toilets, vanities, fixtures), and 20% for diagonal patterns, herringbone layouts, or natural stone. Always round up to whole boxes.
How many 12x12 tiles in a box?
Most 12×12 ceramic tile boxes contain 10–12 tiles, covering 10–12 square feet. Porcelain 12×12 boxes are similar but heavier. Always check the box label — manufacturers vary, and some 12×12 boxes hold as few as 8 tiles or as many as 15.
How many 6x24 plank tiles do I need for 100 sq ft?
Each 6×24 tile covers 1 square foot, so 100 sq ft needs 100 tiles plus a 15% waste factor for plank patterns = 115 tiles. Plank tiles waste more than grids because of the staggered offset cuts at each end of every row.
Should I buy extra tile?
Always. Buy 10–20% extra at minimum, and consider buying one extra box on top of that for future repairs. Tile dye lots vary, and matching tile from a different production batch a year later is nearly impossible. Spare tiles also let you replace a cracked or damaged piece without retiling the whole room.
What grout gap should I use?
1/8 inch is the standard for most ceramic and porcelain tile floors and walls. Use 1/16 inch for rectified large-format tiles where you want a tight, modern look. Use 3/16 to 1/4 inch for natural stone (slate, travertine) or rustic looks where slight tile size variations need more grout to hide.
Can I use this calculator for wall tile and backsplashes?
Yes — the math is identical. Just enter the wall area instead of the floor area. For a kitchen backsplash, measure from the countertop to the underside of the upper cabinets, multiply by the run length, and subtract any window or outlet cutouts.
How much does it cost to tile a 100 sq ft room?
Material costs typically run $1–$15 per sq ft depending on tile choice (ceramic at the low end, porcelain mid-range, natural stone at the top). Add $5–$15 per sq ft for professional installation. A 100 sq ft room is therefore roughly $600–$3,000 installed, plus grout, thinset, and supplies.
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