Jake Morrison, Licensed General Contractor · Last reviewed April 28, 2026

Tile Calculator

Calculate exactly how many tiles, boxes, bags of thinset, and grout you need — for any layout pattern, across up to five areas. Printable shopping list, no signup, no email.

Tile calculator: enter your area and tile dimensions

Area 1

ft
ft
in
in

Tiles laid in a regular grid, edges aligned. Easiest layout, fewest cuts. Standard 10% waste covers cuts at the perimeter.

1/8" Standard for porcelain & ceramic.

Enter your area and tile dimensions above to see how many tiles, boxes, and bags of thinset and grout you need.

Estimates only. This calculator gives you a strong starting point for material orders, but every job has surprises — uneven walls, unsquare rooms, unexpected layout cuts. Always verify against your tile manufacturer's box coverage and your specific bond pattern before purchase. When in doubt, order one extra box; you'll thank yourself when you crack a tile two days into install.

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How to use this calculator

  1. Measure each room you're tiling — length and width in feet. If you've got a kitchen + entry + backsplash, that's three areas. The calculator supports up to five at once and adds them up for you. Round irregular spaces to the nearest rectangle that contains the tile area; you'll be ordering an extra box anyway and the waste % covers small differences.
  2. Pick your tile size from the preset row (subway, 4×4, 12×12, 12×24, slab, etc.) or enter a custom dimension in inches. The presets cover the eight sizes that account for ~90% of residential installs.
  3. Choose your layout pattern. This is the part most online calculators get wrong — they let you pick a pattern but don't change the waste %. Mine does. Straight grid is +10% waste; running bond +12%; diagonal +15%; herringbone +18%; Versailles / French +20%. Those numbers come from the TCNA Handbook and 14 years of throwing broken tiles in a bucket.
  4. Set your grout joint width. 1/8" is the default for porcelain and ceramic. Polished stone and rectified porcelain go tighter (1/16"); slate and travertine go wider (1/4–3/8"). The little visual on the right shows you what the gap looks like at scale.
  5. Enter the tiles per box (it's printed on the tile spec sheet — usually 6 to 30 depending on tile size). The calculator will round up to whole boxes and tell you how many surplus tiles you'll have. If you don't know yet, leave it blank — you'll still get the tile count.
  6. Print or copy the shopping list. The PDF is branded, dated, and lists tiles, boxes, thinset bags, grout bags, spacer count, and a backer-board reminder. Hand it to whoever's running to the home center.

Why this tile calculator is different

Most tile calculators online give you the count and stop. After fetching the top five SERP results to compare, here's what's typical online versus what this one adds:

  • Most calculators don't change the waste % when you pick a pattern. They ask "what's your layout?" but the underlying math doesn't shift. If you put your tile on the diagonal, you're cutting triangles at every wall and you'll burn 15% — pick herringbone and it's closer to 18%. This calculator wires the pattern picker directly to the waste percentage so the order matches the install.
  • Most don't sum multiple areas while also rounding to boxes. One tool does multi-room (Best Tile), one does box rounding (Omnicalculator) — none do both. Real renovations have a kitchen and an entry and a backsplash, all in one trip to the supplier. This one runs the full sum.
  • Most don't tell you about thinset, grout, or spacers. You buy 100 sq ft of tile and walk past the mortar aisle empty-handed. This calculator pulls coverage rates from the Mapei Ultracolor chart and Custom BP's VersaBond data sheet so the bag count is on the list.
  • Nobody offers a printable shopping list. The PDF that comes out of this calculator is dated, branded, and includes a backer-board reminder. Take it to Lowe's, hand it to your spouse, or attach it to your contractor email.
  • Nobody offers an embed. If you write about tile (installer blog, /r/HomeImprovement mod, kitchen-remodel forum) the iframe at the bottom of this page lets you host the same calculator with attribution. Free.

How it works (the math behind the numbers)

The core calculation is dead simple. Three lines of math: 

effective_tile_area = (tile_length + grout_gap) × (tile_width + grout_gap)
tiles_needed       = ceil(area / effective_tile_area × (1 + waste_pct))
boxes              = ceil(tiles_needed / tiles_per_box)

The effective tile area includes the grout joint, because the joint takes up real floor — you can't ignore it on a 4×4 tile with a 1/4" gap (that's a 12% area difference). The waste % comes from the layout pattern; that's the part most online calculators leave manual. Cross-checked against Calculator.net and the TCNA Handbook; my fixture file with 10 input → output pairs runs as a build-time gate so the numbers can't drift.

For thinset, the calculator classes your tile by average dimension (small ≤4", medium ≤12", large ≤18", slab >18") and applies the per-square-foot coverage from Custom BP's VersaBond LFT data sheet — small tiles eat more thinset because of the higher edge-to-area ratio. Grout coverage works the same way, but it also scales with joint width: a 1/4" joint takes twice the grout of a 1/8" joint, all else equal. Spacer count is 4 per tile (one per corner) plus 5% for the inevitable lost-spacer-in-the-bucket loss.

Three real-world examples

Kitchen floor — 12×12 porcelain, straight grid

10 ft × 12 ft kitchen = 120 sq ft. 12×12 porcelain at 1/8" grout, straight layout (10% waste), 10 tiles per box. The calculator returns: 130 tiles, 13 boxes, 9 bags of thinset, 1 bag of grout, 547 spacers. The 10 surplus tiles cover the broken-tile-during-cut tax. If you're tiling a kitchen and the calculator says fewer than 1 surplus tile, you're under-ordered — bump up to the next box.

Subway-tile backsplash — 3×6 ceramic, running bond

5 ft long × 3 ft tall (above counter to upper cabinets) = 15 sq ft. 3×6 ceramic at 1/16" grout (rectified subway), running bond (+12% waste), 30 tiles per box. The calculator returns 131 tiles, 5 boxes, 2 bags of thinset, 1 bag of grout, 551 spacers. Backsplashes look small but they eat tiles fast — the 12% waste matters. The bigger gotcha on backsplashes is the cuts at the upper-cabinet edge and around outlets. If you've got two outlets and a switch, plan on losing 4–6 tiles to those cuts alone.

Bathroom floor — 6×6 ceramic, herringbone

Small bathroom: 8 ft × 7 ft = 56 sq ft, but you've got a 5 ft tub, so net floor is closer to 35 sq ft. Round to 5 ft × 7 ft. 6×6 ceramic at 1/4" grout (handmade rustic look), herringbone (+18% waste), 20 tiles per box. The calculator returns roughly 165 tiles, 9 boxes, 3 bags of thinset, 1 bag of grout, 695 spacers. Herringbone in a small space is the highest-waste / highest-cut combo — every wall needs a triangular fill piece. The 18% waste is the difference between a clean install and a second trip to the tile supplier mid-job.

What affects how many tiles you actually need

The calculator gives you a strong starting point, but a real install has variables it can't see:

  • Squareness of the room. Almost no residential room is square. Walls drift up to 1/2" over 10 feet. The longer wall determines your starting line, and the cut tiles on the short wall get progressively wider or narrower. If your room is significantly out of square, plan for an extra 5% waste on top of pattern waste.
  • Cuts at obstacles. Toilets, vanities, hood vents, kitchen islands, outlets, transitions — every obstacle eats a tile or two in cut waste. Two obstacles in a 50 sq ft bathroom can eat 3–5 tiles before you realize it.
  • Broken tiles during cutting. Wet-saw cuts on porcelain are clean, but wall tiles with score-and-snap break unevenly about 10% of the time. Larger format (≥12") is more breakage-prone than smaller. If you're new to a wet saw, give yourself a 4–5 tile practice budget and cut on the test pieces before committing.
  • Dye lot variation. Tile boxes are stamped with a dye lot. If your supplier sells you boxes from two lots, the color variation can be visible on a long run. Always order a single dye lot, even if it costs an extra trip.
  • Future repair stock. When the install's done, save 5–10 surplus tiles in the basement. Five years from now, when the dishwasher leaks and the floor cracks, the dye lot is gone and a single replacement tile from the current supply will be a visible patch. The 10–20% waste % covers install and a small repair cache.

For tile-cutting itself — the actual saws, the right blade, the diamond bits, the wet vs dry decision — see Jake's writeups on cordless drills (for cement-board screws and thinset mixing) and shop vacuums (for thinset cleanup and tile dust before grouting). And if you're planning your first full bathroom or kitchen tile job, the essential homeowner tool list covers the supporting cast.

Frequently asked questions

How do I calculate how much tile I need?

Multiply the room length and width in feet to get the area in square feet, then divide by the tile area (in square feet) to get the number of tiles, then add 10–20% waste depending on layout. The shortcut: use this calculator. The reason this kind of math goes wrong by hand is the grout-joint adjustment — a 12×12 tile with 1/8" grout doesn't actually cover 1 sq ft per tile, it covers about 0.98 sq ft. On a 100 sq ft room that's 2 extra tiles you'd miss.

What is the 3-4-5 rule for tiling?

It's a square-checking trick from the Pythagorean theorem. Mark 3 ft along one chalk line and 4 ft along the perpendicular chalk line; the diagonal between those marks should measure exactly 5 ft. If it does, your two reference lines are at a true 90°. If they're not, your tile rows will drift visibly across the floor, especially with running bond or herringbone. Always 3-4-5 before you set the first tile.

Are 12×12 tiles actually 12×12?

Mostly yes for porcelain and rectified ceramic — they're cut to within a millimeter or so of the nominal size. Hand-finished and tumbled tiles can vary by 1/8" or more. For most residential porcelain installs, treat 12×12 as 12×12 for calculator purposes; if you're doing artisanal handmade tile, measure 5–10 from the box and use the average.

How much extra tile should I order?

10% on a straight install with no cuts; 12% on running bond / subway pattern; 15% on diagonal; 18% on herringbone; 20% on Versailles / French. This calculator applies those percentages automatically when you pick the layout. If you're new to tile work, bump it 5% — the practice tax is real.

Can I embed this tile calculator on my site?

Yes — copy the iframe snippet at the bottom of this page. The embedded version is a stripped-down variant designed for installer blogs, /r/HomeImprovement, kitchen-remodel forums, and tile-supplier sites. Required attribution is built in. Free, no signup, no analytics attached to the embed.

Tile work has a tighter required-tool list than most renovation jobs. Beyond the wet saw or score-and-snap cutter, here's what's on every Morrison-Construction tile job:

  • Best Cordless Drills — for cement-board screws, mixing thinset with a paddle attachment, and pilot holes through grout.
  • Best Shop Vacs — tile dust ruins household vacuums. A dedicated shop vac handles thinset cleanup, grout-joint clearing before grouting, and post-cure cleanup.
  • Best LED Shop Lights — tile lippage and grout-line waver only show up under raking light. A bright, even shop light at floor level catches problems while you can still fix them.
  • Essential Tools for New Homeowners — the 12-tool starter kit before any DIY tile project.

Sources & methodology

This calculator is reviewed annually for source currency. About Jake · Last reviewed April 28, 2026.

Embed this tool on your site

Free for tile-installer blogs, kitchen / bath remodel forums, /r/HomeImprovement and /r/Tile mods, tile-supplier sites, and personal renovation logs. Required attribution is included in the snippet. No fee, no account, no analytics attached to the embed. 

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<p style="font-size:12px;color:#666;margin-top:8px">
  Tile calculator by
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  &middot; Reviewed by Jake Morrison, Licensed GC
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