Tile Calculator
Find out how many tiles (and boxes) you need to buy for a floor or wall.
Area and tile size
Results
For a 10 ft × 10 ft area, tiled with 12 in × 12 in tiles in a straight layout, you'll need about 108 tiles (11 boxes).
Tile needed
11 boxes
That's a typical amount for a standard kitchen, bathroom, or mid-size room floor.
Order it all from the same production run if possible — ask your retailer to confirm matching lot numbers across the full order, since a second trip later risks a subtle shade or texture difference.
Area to cover: 100 sq ft
Area including waste allowance: 110 sq ft
Individual tile count: 108 tiles
How this works
The floor or wall area (length x width) is inflated by a waste-factor percentage — 10% for a straight/grid layout, 15% for diagonal or other patterned layouts — to cover cutting waste, breakage, and future repair stock. That inflated area is then divided by a single tile's laid footprint, which is the tile's own length and width each increased by one grout-joint width, since the grout line is physically part of what each tile occupies once installed. The result is rounded up to the next whole tile, since partial tiles can't be purchased, and — if you enter a tiles-per-box figure — divided by that number and rounded up again to a whole box. Standard waste-factor figures come from major retailer tile installation guides and industry association technical guidance (see the Common Mistakes and FAQ sections above and below for layout-specific detail); your specific tile product's packaging may state its own coverage-per-box figure, which is worth cross-checking against this calculator's box estimate before ordering. This calculator assumes a single rectangular area and a single tile size — for irregular rooms or mixed tile sizes, see the FAQ above for how to split your calculation. The two-tier waste factor (10% vs 15%) is a deliberate simplification of what's actually a continuous relationship between cut-edge density and layout complexity — a straight grid genuinely produces fewer, simpler cuts than a diagonal or herringbone layout, but within each category there's real variation depending on room shape, obstruction count, and installer skill. Treating layout as a binary choice keeps the calculator usable without asking for a dozen inputs, at the cost of some precision at the edges of each category (see the edge cases above for where that simplification runs thinnest — large-format tile, complex geometric patterns, and very small rooms all push the true waste ratio away from the flat 10%/15% figures in a predictable direction). If your project sits at one of those edges, treat this calculator's output as a starting point and adjust the waste factor manually before ordering, rather than assuming the default fits every layout equally well. The grout-footprint calculation similarly assumes every tile in the room is full-size and rectangular; it does not attempt to model the reduced grout consumption of cut pieces along a wall, since cut-piece grout usage varies too much by installer technique to standardize. Waste factor guidance (10% straight, 15% diagonal/pattern): The Home Depot tile installation guide.
Worked example
A 10 ft x 10 ft bathroom floor (100 sq ft), tiled with standard 12in x 12in tiles at a 1/8in grout joint, straight layout, 10% waste: each tile's laid footprint is about 12.125in x 12.125in, or roughly 1.02 sq ft including its share of grout. Applying 10% waste to the 100 sq ft floor gives 110 sq ft to cover; dividing by the ~1.02 sq ft footprint gives about 108 tiles needed. If the tile is sold 10 to a box, that's 10.8 boxes — rounded up to 11 boxes, since you can't buy a partial box.
A second example: a diagonal-pattern living room floor
A 15 ft x 20 ft living room (300 sq ft), tiled with the same 12in x 12in tiles at a 1/8in grout joint, but laid diagonally: the waste factor jumps to 15% instead of 10% because of the angled corner and edge cuts a diagonal layout requires. That's 345 sq ft to cover; at the same ~1.02 sq ft footprint per tile, that's about 338 tiles. At 10 tiles per box, that's 33.8 boxes, rounded up to 34 boxes — five more boxes than the same 300 sq ft floor would need in a straight layout, purely because of the pattern choice.
Common mistakes
Ignoring grout width entirely
Treating grout as zero-width and dividing floor area by bare tile dimensions alone. It seems like a rounding error at small grout widths, but for a large floor with many tiles, even a 1/8in joint compounds into a real difference between the naive estimate and the true tile count — this calculator always factors grout width in.
Using the straight-layout waste factor for a diagonal or herringbone pattern
Defaulting to 10% waste out of habit even when the layout is diagonal, herringbone, or another pattern with angled cuts. These patterns genuinely produce more unusable offcuts, and running out of tile mid-installation on a discontinued product can mean living with a visible seam or mismatched dye lot in a highly visible pattern area.
Forgetting that box counts round up, not to the nearest box
If a box contains 10 tiles and you need 103 tiles, you need 11 boxes, not 10.3 rounded to 10. This calculator rounds raw tile count up to a whole tile first, then computes boxes from that — always round the final box count up as well, never down, even if the fractional remainder looks small.
Measuring only once, from a single reference point
Rooms are rarely perfectly rectangular even when they look it — walls can bow, and corners are rarely exactly 90 degrees. Measure length and width at more than one point (near each end of the wall) and use the largest reading for each dimension, so your tile order doesn't come up short against a wall that's slightly longer than your first measurement suggested.
Assuming all tile from the same product line matches exactly across orders
Natural stone and some ceramic/porcelain lines vary in shade between production runs (dye lots). Buying in one order with the waste buffer built in avoids a second order that might not match — if you do need a second order later, ask specifically for the same lot number, and expect the retailer may not be able to guarantee it.
Not accounting for the transition/threshold strip separately
Where tile meets carpet, hardwood, or another room, most installations need a transition strip — this calculator estimates field tile only, not trim, transition strips, or bullnose edge pieces, which are typically bought separately by linear measurement of the doorway or edge, not by area.
Applying the waste factor to a total that already includes a border or accent strip
If you've combined field tile and border/accent tile into one blended area before running this calculator, the single waste factor gets applied unevenly — border strips usually need a higher cut ratio than field tile. Keep field and border areas separate (see the FAQ above) so each gets an appropriate waste factor rather than one averaged figure.
When this calculator's model stops applying
- Large-format tile (24in and up per side): waste factors developed for standard 12in tile may run slightly high for large-format tile, since fewer, larger tiles mean fewer total cut edges relative to floor area — some installers use a lower waste factor (around 7-8%) for large-format straight layouts. Adjust the waste factor manually if you're working with large-format tile.
- Mosaic or sheet-mounted tile (small tiles pre-mounted on mesh sheets): this calculator's per-tile grout model doesn't map cleanly onto sheet-sold mosaic, which is priced and ordered by sheet, not by individual tile. Use the sheet's coverage area (often listed in sq ft per sheet) directly instead of this calculator.
- Herringbone and other complex geometric patterns beyond simple diagonal: 15% is a reasonable starting point, but some intricate patterns (chevron, basketweave with multiple tile sizes) run higher in practice — installers sometimes budget 18-20% for the most complex patterns. Treat 15% as a floor, not a ceiling, for unusually complex layouts.
- Uneven or out-of-level subfloors: significant leveling work can change effective grout width in practice (installers sometimes widen joints slightly to accommodate a subfloor that isn't perfectly flat), which this calculator doesn't model. Budget extra tile if your installer has flagged subfloor leveling issues.
- Very small rooms or areas under roughly 20 sq ft: at this scale, the fixed cost of corner and edge cuts is large relative to the total area, so both waste factors tend to run low in practice — consider adding a couple of extra tiles beyond the calculated amount regardless of what the waste-factor math suggests, since a very small order is cheap insurance against a repeat trip.
- Radiant floor heating installations: some radiant heat systems recommend specific tile thicknesses or slightly wider grout joints for thermal expansion, which changes the tile footprint from what this calculator assumes by default — check your radiant system manufacturer's tile installation guidance before finalizing your order.
- Non-rectangular individual tiles (hexagon, picket, arabesque): the grout-footprint math this calculator uses assumes a rectangular tile whose laid footprint is simply its length and width plus one grout joint on each dimension. Hexagonal and other non-rectangular shapes tile a surface differently and typically come with their own coverage-per-box figure from the manufacturer — use that figure directly rather than this calculator's per-tile math for non-rectangular shapes.
- Tile ordered from a discontinued or limited production run: if the specific tile you want has already been marked discontinued or is from a limited one-time production run, the standard 10-15% waste buffer may not be enough insurance, since a future repair may be impossible regardless of how much extra you buy now. Consider buying a noticeably larger buffer (an extra box or two beyond the calculated waste factor) specifically to cover future repairs, since re-sourcing an exact match later may not be possible at any price.
- Tile with a directional pattern or veining that must be rotated or bookmatched: some porcelain and natural stone lines are designed to alternate orientation tile-to-tile (a running or basketweave veining effect), which typically needs slightly more tile than a same-orientation layout because certain cuts can't be reused from adjacent tiles. Budget a few extra percent above the standard waste factor if your chosen tile calls for directional layout.
FAQ
Why does grout width change how many tiles I need?
Every tile you lay actually occupies more floor space than its bare dimensions, because the grout line around it takes up room too. A 12in x 12in tile with a 1/8in grout joint effectively claims about 12.125in x 12.125in of floor per tile once it's set. Wider grout lines mean each tile-plus-joint unit covers more area, which slightly reduces the tile count — but it also uses more grout, so the tradeoff isn't free.
Should I round the tile count up or buy exact?
Always round up to the next whole tile, and this calculator already does that for you. Buying exact-to-the-tile is a common mistake: a single miscut, a chipped edge on install day, or a broken tile discovered years later during a repair can leave you unable to source the same dye lot, since tile production runs change over time.
What's the difference between straight and diagonal waste factors?
A straight (grid) layout runs tiles parallel to the room's walls, so most cuts are simple straight edge cuts with minimal waste — a 10% buffer is standard. A diagonal layout runs tiles at a 45-degree angle to the walls, which means every tile touching a wall or corner needs an angled cut, producing more unusable offcut triangles — 15% is the standard buffer for diagonal and other complex patterns like herringbone.
Does this calculator account for tile breakage during shipping?
Indirectly, yes — the waste factor (10-15%) is a general buffer that covers cutting waste, on-site breakage, and future repair stock together, not a separate line item. If you're ordering a fragile or handmade tile known for a higher-than-usual breakage rate, consider manually bumping the waste factor a few points higher than the default.
How do I handle an L-shaped room or a room with a closet alcove?
Split the space into rectangles, run this calculator once per rectangle using each rectangle's own length and width, and add the resulting tile counts together. Don't try to average one length and one width across the whole irregular footprint — that undercounts the corners and overcounts the middle.
Are boxes always a fixed number of tiles?
Not always, but it's the common case for factory-boxed tile, and that's what this calculator assumes when you enter a tiles-per-box figure. Some tile lines are sold by weight or by square-foot-per-box rather than a fixed tile count per box — check your specific product's packaging, since box coverage can vary by size and thickness within the same tile collection.
Do wall tiles need a different waste factor than floor tiles?
The waste-factor logic (10% straight, 15% diagonal/pattern) applies the same way to walls as to floors, since it's driven by layout geometry rather than which surface the tile sits on. What differs for walls is that you're more likely to have obstructions (outlets, fixtures, a window) that eat into usable area — measure the wall's gross area and treat each obstruction the way this calculator treats doors and windows on the paint calculator: subtract it before you calculate, or budget extra tile to cover it.
Why is my in-store estimate different from this calculator's result?
Big-box retail calculators often use a single flat waste percentage regardless of layout pattern, or round box quantities differently. This calculator separates straight and diagonal waste factors and lets you adjust grout width, tile size, and waste factor individually, which tends to produce a tighter, more situation-specific estimate — but always sanity-check against your specific tile product's packaging, since box coverage claims vary.
Can I use this for a bathroom floor with lots of fixtures?
Yes, but measure the gross floor area first and don't manually subtract the toilet or vanity footprint the way you'd subtract a door on the paint calculator — installers typically still need to cut tile around those fixtures rather than skip that area entirely, so the standard waste factor already accounts for some of this. For a small, fixture-heavy bathroom, consider bumping the waste factor up a few points since the ratio of cut edges to whole tiles is higher in a small room.
What if I'm mixing two tile sizes in one room (a border or accent strip)?
Run the calculator twice — once for the field tile area at its size, once for the border/accent area at its size — and buy each separately. Combining two tile sizes into one average-size calculation will misestimate both, since the accent strip's grout ratio and cut pattern are usually very different from the field tile's.
Does grout width change how much grout I need to buy, not just the tile count?
Yes, and they move in the same direction for different reasons: a wider grout joint slightly reduces the tile count (each tile-plus-joint unit covers a bit more area) but increases the volume of grout you need per square foot, since there's more joint to fill. This calculator estimates tile and box count only — grout quantity is a separate calculation based on joint width, depth, and tile thickness, usually available on the grout manufacturer's own coverage chart on the bag.
Should I buy tile trim or bullnose pieces using this calculator's output?
No — this calculator estimates field tile by area, but trim pieces (bullnose, quarter-round, edge caps) are sold and measured by linear foot of exposed edge, not by area. Measure the total length of any exposed tile edge (a shower curb, a half-wall, an open stair edge) separately and order trim to that linear measurement, with its own small waste allowance for corner cuts.
Why does the calculator's box count sometimes look wasteful for a small area?
Because whole-box rounding is a real cost that gets proportionally larger the smaller your area is. A 15 sq ft powder room might only need 16 tiles, but if the box holds 10, you're buying 20 — 25% more than the raw calculated need, just to reach two whole boxes. This is expected behavior, not a bug: partial boxes generally aren't sold, so rounding up is the only purchasable option.
Does tile thickness affect how many tiles I need?
Not for the area/count math this calculator performs — thickness affects the tile's weight, how it's cut, and how much thinset mortar and floor buildup height it needs, but not the plan-view footprint the tile-count calculation is based on. Thicker tile (common in some porcelain and natural stone) is worth flagging to your installer separately, since it can affect door clearance and transition height at room thresholds.
What's a reasonable amount to keep in reserve after installation, beyond what's already in the waste factor?
Many installers recommend keeping a small stash — a spare box or a handful of loose tiles — stored flat somewhere dry, specifically for future repairs, on top of whatever the waste factor already covers during the original install. The waste factor is sized for cutting and breakage during installation itself, not for a repair five years later after the tile's original production run may be discontinued.
Related tools
Carpet Calculatorswitching from a hard-surface room to a carpeted one, or comparing material quantities between the two flooring types, before you decide what to buy.Flooring Calculatorcomparing tile against laminate, hardwood, or vinyl plank for the same room before you settle on a material.Grout Calculatoronce you know your tile size and layout, work out how much grout the same job needs.More flooring tools (underlayment calculator) are planned but not yet published.