Tile & Grout Calculator
Calculate how many tiles to buy (with waste for cuts and pattern) and how much grout you need, based on your tile size, grout joint width, and tile thickness.
Planning a tile job? This tells you how many tiles to buy (with waste for cuts) and how much grout you'll need — figured from your tile size, joint width, and thickness, not a rough guess. Enter the details below.
Area to tile
Total surface to cover in square feet — length × width. For an L-shaped room or a backsplash with sections, add the pieces together.
Tile size
Pick a common size or choose Custom to enter your own.
Grout joint width
Gap between tiles. Narrow joints (1/16") suit rectified and wall tile; wider joints (3/16"–1/4") suit rough or handmade tile.
Tile thickness
How thick the tile is — affects grout volume. Most ceramic is about 1/4", porcelain 3/8", natural stone 1/2".
Layout pattern
How the tile is laid. Diagonal and herringbone layouts need more tile because the angled cuts at edges create more waste.
Waste allowance
Extra tile for cuts, breakage, and future repairs. The pattern sets a typical default; bump it up for a complex room with lots of cuts.
Tiles to Buy
132
12"×12" tile for 120 sq ft + 10% waste
Before you buy
Your 1/8-inch joints call for sanded grout, which resists shrinkage and cracking in wider lines. Order all your tile from the same dye lot in one go — color varies between production batches — and set aside a few spares afterward for future repairs. Buying a little beyond this estimate covers miscuts and breakage.
Tile counts include your waste allowance and round up to whole tiles; grout uses a standard coverage formula from your tile size, joint width, and thickness, calibrated to typical product charts and rounded up to 25-lb bags (smaller 10-lb and 8-lb bags exist for small jobs). This estimate doesn't include thinset/mortar, backer board, or trim pieces. Mosaic and sheet-mounted tile are sold by the sheet, not the piece — use the area and grout figures and buy sheets to cover the square footage. Always confirm against your product's stated coverage.
💡About this calculator▼
Two questions decide your tile shopping list: how many tiles, and how much grout. Get the tile count wrong and you risk a dye-lot mismatch when you go back for more; underestimate the grout and you're back at the store mid-job with half a floor done. This calculator nails both before you buy.
Enter the area you're tiling, pick your tile size (or enter a custom one), set the grout joint width, tile thickness, and layout pattern, and you'll get the number of tiles to buy — including a waste allowance for cuts and breakage — plus the pounds and bags of grout.
The grout figure is where this calculator earns its keep. Grout isn't a flat amount per square foot: it depends on a real relationship between your tile size, the width of the grout joints, and how thick the tile is. Tiny mosaic tiles with wide joints can use ten times the grout of big-format tiles with tight joints over the same area. Instead of guessing, this tool runs the actual coverage math.
The calculator works out two separate quantities — tiles and grout — from the same set of inputs.
For tiles, it divides your area by the area of one tile to get the base count, then adds a waste allowance for the cuts, breakage, and future repairs every job needs. The layout pattern drives that waste: a straight (grid) lay wastes about 10%, a diagonal lay about 15%, and a herringbone or other intricate pattern about 20%, because angled cuts at the edges leave more unusable offcuts. You can adjust the percentage for an especially cut-heavy room. The result is rounded up to whole tiles.
For grout, it uses the standard coverage relationship: grout needed per square foot rises as tiles get smaller (more joint length packed into the area), as joints get wider, and as tiles get thicker (deeper joints to fill). A 2-inch mosaic with 1/4-inch joints needs far more grout than a 24-inch plank with 1/16-inch joints. The tool multiplies that per-square-foot figure by your area, then rounds up to standard 25-pound bags.
The grout factor is calibrated to typical manufacturer coverage charts and rounds conservatively — because running out of grout partway through a floor, then getting a slightly different shade from a new batch, is exactly what you want to avoid. The exact formula and a worked example are below.
📐How it's calculated▼
The estimate computes tiles and grout separately, and rounds both up.
Tiles: Tile area (sq ft) = (Tile length × Tile width) ÷ 144 Base tiles = Area ÷ Tile area Tiles to buy = Base tiles × (1 + Waste % ÷ 100), rounded up
Grout (pounds): Grout per sq ft = [(Tile L + Tile W) ÷ (Tile L × Tile W)] × Joint width × Tile thickness × 16 Total grout = Grout per sq ft × Area (All tile measurements in inches; the factor 16 is calibrated to typical product coverage.) Bags = Total grout ÷ 25, rounded up
Example: 120 sq ft, 12 × 12 in tile, 1/8 in joints, 1/4 in thick, straight lay (10% waste)
→ Tile area: (12 × 12) ÷ 144 = 1 sq ft
→ Base tiles: 120 ÷ 1 = 120
→ Tiles to buy: 120 × 1.10 = 132
→ Grout per sq ft: [(12 + 12) ÷ 144] × 0.125 × 0.25 × 16 = 0.083 lb
→ Total grout: 0.083 × 120 ≈ 10 lb → one 25-lb bag
Swap to 2-inch mosaic tiles and the grout for the same 120 sq ft jumps roughly six-fold — a vivid reminder that small tiles drink grout.
📎Source: Tile Council of North America (TCNA) — Installation Guidelines
🔍Finding your inputs▼
Area to tile: The total surface in square feet — multiply length by width for a simple rectangle. For an L-shaped floor or a backsplash that wraps a corner, break it into rectangles and add them. Measure the actual tiled surface; don't subtract small fixtures like a toilet flange or a faucet, since you'll cut around them and those cuts become waste anyway.
Tile size: Choose a common size or pick Custom and enter the length and width in inches. This is the single biggest factor in both the tile count and the grout amount, so use the real face dimensions of your tile (a "12-inch" tile is usually a true 12 inches, but some nominal sizes run slightly under).
Grout joint width: The gap between tiles. Narrow 1/16-inch joints suit rectified (precisely cut) tile and many wall installations; 1/8 inch is the most common all-purpose joint; 3/16 to 1/4 inch suits rougher, handmade, or natural tile where size varies. Wider joints use more grout — and change which grout type you need (see below).
Tile thickness: How thick the tile is, which sets how deep the grout joints are. Most ceramic wall and floor tile is about 1/4 inch, porcelain around 3/8 inch, and natural stone 1/2 inch or more. Thicker tile means deeper joints and more grout.
Layout pattern: How the tiles are arranged. A straight grid is the most efficient; diagonal (45°) and herringbone layouts produce more edge cuts and therefore more waste, so they bump the default waste allowance up. Pick the one that matches your plan.
Waste allowance: The extra tile beyond the bare area, for cuts, breakage, and keeping spares. The pattern sets a sensible default (about 10/15/20% for straight/diagonal/herringbone), but raise it for a small or choppy room with many cuts, lots of corners, or expensive tile you can't easily re-order in the same dye lot.
⚠️Special situations▼
I'm using small mosaic or sheet-mounted tile
Mosaics and many small tiles come pre-mounted on 12x12-inch mesh sheets and are sold by the sheet, not the individual piece — so the per-tile count here will look huge and isn't what you order. Instead, use the area and the grout figure: buy enough sheets to cover your square footage (plus waste), and trust the grout pounds, which the formula computes correctly for the small tile size and its many joints. Small mosaics genuinely use a lot of grout, so don't be surprised by the number.
Should I use sanded or unsanded grout?
It comes down to joint width. Use unsanded grout for narrow joints, 1/16 inch and under — it packs into thin lines and won't scratch polished or glass tile, where sand grains would. Use sanded grout for joints 1/8 inch and wider, where the sand gives it body and keeps it from shrinking and cracking. The calculator notes which type your chosen joint width calls for. If you're unsure, 1/8 inch with sanded grout is the most common all-purpose combination.
My room has lots of cuts, corners, or angles
The more cuts a layout requires, the more offcuts you can't reuse, so bump the waste allowance above the pattern default. A small bathroom packed with a tub, toilet, and vanity, or a room with many jogs and niches, can justify 15–20% even for a straight lay. Large-format tile also wastes more when cut, because a single bad cut ruins a big, expensive piece. When tile is costly or hard to re-order, err on the high side — leftover full tiles are useful spares.
How do I turn tiles into boxes to buy?
Tile is sold by the box, and each box lists either a piece count or a square-foot coverage. If it lists pieces per box, divide the tiles-to-buy number here by that and round up. If it lists coverage, divide your area-plus-waste square footage by the box coverage and round up. Either way, round up to whole boxes and buy them all at once from the same dye lot — partial boxes from a later batch are the classic source of a visible color shift across a floor.
I want to keep spare tiles for the future
Smart — and the waste allowance already leaves you some. Tiles get discontinued, and even the same product varies by dye lot, so a cracked tile years later is nearly impossible to match perfectly without spares from your original batch. Keep at least a few full tiles (a partial box is ideal) stored flat and dry. If you want a deliberate stash beyond normal cuts, add a couple of percent to the waste allowance so the count reflects it.
❓Common questions▼
How many tiles do I need?
Divide the area you're tiling by the square footage of one tile, then add a waste allowance for cuts and breakage — about 10% for a straight layout, 15% for diagonal, and 20% for herringbone or intricate patterns. For example, 120 square feet of 12×12-inch tile (1 sq ft each) needs 120 tiles plus about 10%, so 132. Enter your specifics above and the calculator does this for you, then you divide by the tiles-per-box to know how many boxes to buy.
How much grout do I need?
It depends on far more than the area: grout use rises sharply with smaller tiles, wider joints, and thicker tiles, because all three mean more joint volume to fill. A large-format floor with tight joints might use only a pound or two of grout per 20 square feet, while a mosaic with wide joints can use several times that. This calculator runs the actual coverage formula from your tile size, joint width, and thickness rather than a flat guess, and rounds up to whole bags.
How much extra tile should I buy for waste?
Plan on about 10% over the bare area for a standard straight layout, 15% for a diagonal lay, and 20% for herringbone or other cut-heavy patterns. Go higher — up to 20% even for simple layouts — in small or choppy rooms with many cuts, with large-format tile that's costly to mis-cut, or when the tile may be hard to re-order in a matching dye lot. The leftover full tiles double as spares for future repairs, so erring high is rarely wasted.
What is the difference between sanded and unsanded grout?
Sanded grout contains fine sand that gives it strength and keeps it from shrinking or cracking in wider joints — use it for joints 1/8 inch and wider. Unsanded grout is smoother and is used for narrow joints, 1/16 inch and under, where sand wouldn't pack in, and on scratch-prone surfaces like polished stone or glass tile. Joint width, not tile type, is the deciding factor; this calculator flags which one your chosen joint calls for.
Does this calculator include thinset or mortar?
No — it covers tile and grout only, since those are the two quantities tied directly to your tile size and joints. Thinset (the adhesive mortar under the tile) depends mostly on your trowel notch size and the tile format, and is estimated separately; as a rough guide, a 50-pound bag of thinset sets roughly 60–95 square feet of medium tile. Backer board, waterproofing, and edge trim are also separate line items to add to your list.