If you are standing in a tile showroom or staring at a measuring tape in your bathroom, the same question hits every homeowner mid-remodel: exactly how many tiles do I need to buy? Order too few and your project stalls waiting on a backorder. Order too many and you are paying for tile that sits in a garage forever. This guide walks you through every step of the math, gives you a quick-reference tile-per-square-foot table for common sizes, and answers the overage question in full so you know exactly how much extra tile to order based on your pattern. We refreshed this post in 2026 with new coverage tables and pattern-based overage data to make it the only tile quantity resource you will need.
How to Measure the Area You Are Tiling
Every tile count starts with a reliable square footage number. Rushing this step is the single fastest way to end up short on tile, so take your time and measure twice.
Square and Rectangular Areas
Multiply the length by the width. Convert any inches to a decimal before you multiply: divide the inch count by 12 and add it to the whole-foot count. A wall that is 9 feet 6 inches becomes 9.5 feet. If your result is not a whole number after calculating, round up to the nearest square foot. That rounding cushion is small, but it is free insurance.
Circular or Curved Areas
Square the radius (half the diameter) and multiply by 3.14. A circular hearth with a 3-foot radius covers roughly 28.3 square feet (3 x 3 x 3.14). Round up to 29 square feet before you apply overage.
L-Shaped or Irregular Areas
Break the space into rectangles, calculate each piece separately, then add the totals together. An L-shaped floor with one 4 x 6 section and one 4 x 8 section gives you 24 + 32 = 56 square feet. This approach works for any irregular footprint: keep dividing until every piece is a simple rectangle or square, then sum them up.
One extra step worth taking: subtract any fixed obstacles you will not tile around, such as a kitchen island base or a built-in vanity. Those square footage reductions help you order more accurately, though you should still apply your full overage percentage to the adjusted total afterward.
Tile-Per-Square-Foot Quick Reference
Once you have your square footage, you can figure out how many individual tiles you need or verify that your box quantities add up. The table below gives you the coverage math for the most common tile sizes. All figures assume standard grout joints; wider joints reduce coverage slightly, so confirm box coverage claims with your supplier if you are using a wide-joint installation.
| Tile Size | Tile Area (sq ft) | Tiles per Square Foot | Tiles Needed for 100 sq ft (before overage) |
|---|---|---|---|
| 6 x 6 in | 0.25 sq ft | 4.0 | 400 |
| 12 x 12 in | 1.00 sq ft | 1.0 | 100 |
| 12 x 24 in | 2.00 sq ft | 0.5 | 50 |
| 18 x 18 in | 2.25 sq ft | 0.44 | 44 |
| 24 x 24 in | 4.00 sq ft | 0.25 | 25 |
| 3 x 12 in subway | 0.25 sq ft | 4.0 | 400 |
| 8 in hex | ~0.38 sq ft | ~2.6 | ~260 |
To use this table: multiply your square footage by the tiles-per-square-foot figure, then add your overage amount (see the next section). If your tile is sold by the box, divide your adjusted tile count by the number of tiles per box and round up to the next full box. Never round down at the final step.
How Much Extra Tile Should You Order? The Overage Rule Explained
This is the question that drives most of the search traffic to this page, and for good reason: getting overage wrong is expensive in both directions. Here is the honest answer.
The industry standard starting point is 10 percent extra. That figure accounts for cuts along edges, the occasional cracked tile during installation, and a small stash of replacements for future repairs. But 10 percent is a floor, not a ceiling. Several factors push that number higher, and knowing which ones apply to your project can save you a second order at a higher price, or worse, an order for a dye lot that no longer matches your installed tile.
Why dye lots matter. Tile manufacturers fire batches of tile together. The color and finish of one batch can vary slightly from the next. If you run short and reorder weeks later, the new tiles may not be a perfect visual match even if the SKU is identical. Ordering enough on the first purchase is not just about math; it protects the look of your finished room for years.
How to calculate overage. Take your net square footage (after subtracting fixed obstacles), multiply it by your overage factor, and add the result back. For a 120 square foot bathroom floor with a 15 percent overage: 120 x 1.15 = 138 square feet to order. Divide that by your box coverage and round up to the next full box.
Order by the full box. Buying a partial box rarely saves money. Most tile suppliers do not accept partial returns, and fill-in orders often come at a higher per-tile price. When you are close to the edge of a box quantity, always go up, not down.
Overage Percentage by Tile Pattern
Your layout pattern has a bigger effect on waste than most homeowners expect. A diagonal layout on the same floor as a straight-set layout can require 5 percent more tile, purely because of the angled cuts at the perimeter. Use the table below to pick the right overage percentage for your project before you place your order.
| Pattern Type | Recommended Overage | Why |
|---|---|---|
| Straight set (grid) | 10% | Fewest cuts, lowest waste. Standard starting point for most floor and wall projects. |
| Brick / offset (1/3 or 1/2 offset) | 10% | Similar waste profile to straight set. Use 12% if the room has many outlets, niches, or fixtures to cut around. |
| Diagonal (45 degrees) | 15% | Every perimeter tile is cut at an angle, creating triangular offcuts that cannot be reused elsewhere. |
| Herringbone | 15-20% | The V-shaped cuts at borders and the pattern direction changes generate significant waste throughout the field. |
| Mosaic sheets | 10% | Sheets are pre-spaced and edge waste is low, but order 10% to handle grout line alignment at seams and borders. |
| Large format (24×24 and up) | 15% | A single mis-cut or cracked tile represents more lost square footage than a small tile would, so the margin for error is lower. |
| Irregular cuts (curved walls, many corners) | 20%+ | Every curve or angled corner multiplies partial tiles. Consult your installer for a custom estimate on complex layouts. |
If your project combines patterns, such as a herringbone accent band inside a subway-tile shower, calculate each zone separately, apply the appropriate overage to each zone, and order as one combined quantity. Do not average the percentages across the whole room; that almost always results in running short on the more complex area.
Common Mistakes That Ruin Your Tile Count
Even homeowners who measure carefully end up short. Here are the mistakes that cause it most often.
Rounding down at any step. Tile math produces decimals constantly. If you need 4.3 boxes, that means 5 boxes, not 4. Round up at the final step and hold that discipline throughout. Mid-calculation rounding errors compound and can shave an entire box off your final order without you noticing.
Measuring the floor plan instead of the tile surface. A shower with three walls and a floor is four separate surfaces. Measure each face individually and sum them, not just the footprint of the shower on the floor plan. This mistake is especially common when estimating subway tile for a surround.
Ignoring grout joint width. A 1/16-inch grout joint on a 6×6 tile is proportionally minor. A 3/8-inch joint on large-format tile meaningfully reduces the surface area each tile covers. For wide-joint installations, verify the box coverage figure with your supplier rather than relying on the label alone.
Assuming walls are square. Residential walls are almost never perfectly plumb or square. Do not start your first tile run tight against a wall. The edge tiles along any wall will likely need to be trimmed, and those cuts consume tile. Budget for this especially in older homes where settling can throw walls out of plumb by a quarter inch or more over a long run.
Skipping the spare tile stash. Whatever you have left over after installation, keep it. Store it flat in a dry location. If a tile cracks two years from now due to subfloor movement or a dropped object, matching it from your leftover stock is fast and costs nothing. Trying to match it from a retailer after the dye lot is gone is an exercise in frustration.
When to Bring in a Pro
The math in this guide is reliable for straightforward rectangular rooms with standard layouts. But tile work inside a bathroom remodel or a full kitchen remodel rarely stays straightforward for long. Niche shelves, steam shower benches, radiant heat underlayment, accent borders, and transitions between tile and hardwood all create variables that compound quickly. A miscalculation on a 200 square foot kitchen floor with large-format porcelain is a costly mistake to absorb mid-project.
At Forge and Bow, material takeoffs are part of the design-build process. We measure every surface, account for every pattern and transition zone, and coordinate a single material order so you are not managing four separate supplier relationships or hoping the dye lots land in the right sequence. If your project is still in the planning phase, or you have hit a wall mid-remodel and need a second set of eyes, reach out to our team and we can take a look.
