Tile Calculator

How much tile do you actually need? This free tile calculator gives DIYers and pro installers an instant materials list for any floor, wall, or full shower — tiles, thin-set bags sized by trowel and tile, grout in pounds and bags using the TCNA grout formula, waterproofing or uncoupling membrane (Ditra, Kerdi, RedGard, Hydro Ban), tile leveling clips, edge-profile sticks, and TCNA EJ171 movement joints with silicone tube counts.

Most tile calculators stop at square footage and a 10% waste guess. Real installations also need the right mortar class (A118.4 vs A118.15 medium-bed for LFT, A118.11 white for glass), the trowel size that hits 95% coverage in wet areas (ANSI A108.5), the correct grout type for the joint width (sanded ≥ 1/8", unsanded narrower, never sanded on glass or polished marble), and proper movement joints every 20–25 ft interior or 8–12 ft in wet/exterior — none of which a square-footage calculator can do.

Free, no signup. Outputs are pure materials — no labor cost, no $/sq ft pretending to be local. Cite TCNA Handbook 2024, ANSI A108/A118:2024, A137.1:2022, ASTM C373/C920, IPC, IRC R702.4. Always order from ONE dye lot to avoid shade variance (ANSI A137.1 §6.3 V0–V4).

View material estimation guides →

Tile Calculator

Floor, wall, or full shower. Returns tiles, thin-set bags by trowel, grout (TCNA formula), waterproofing membrane, leveling clips, edge trim, and TCNA EJ171 movement joints with silicone tubes.

1. Where are you tiling?

Floor, wall, full shower, or freeze-thaw exterior. Drives wet-area rules + 95% coverage.

2. Dimensions

Room 1
ft
ft

3. Tile material & size

Dense — back-butter LFT to reach 95% coverage. Slows modified-mortar cure.

Pick a preset or choose Custom to enter your own dimensions.

in
in
in

Used as joint depth — typical 1/4–3/8"

4. Pattern, joint & installer

5. Substrate

CBU per A118.9 over a flat, fastened subfloor. Tape and thin-set all seams with 2" alkali-resistant mesh.

Small project — do you need a dumpster at all?

Projects this size often fit in a Bagster (up to 3 cubic yards). See how Bagster bags compare to a 10-yard dumpster on cost, access, and material limits.

Compare Bagster vs. Dumpster →

Related Calculators

Flooring Calculator

Instantly calculate flooring sq ft, boxes & cost with waste factor for tile, hardwood, laminate, LVP & carpet. Free, accurate, no signup required.

Backsplash Tile Calculator

Instantly calculate backsplash tiles, grout bags, thinset & trim for ceramic, glass, marble & mosaic. TCNA/ANSI formulas. Free, no signup needed.

Mortar / Thinset Calculator

Pick the right ANSI mortar (A118.1/.4/.11/.15/.3 or A136.1 mastic) for substrate and tile, then get bag count by trowel notch. NTCA, TCNA, ANSI A108.

How to Use This Calculator

  1. Pick application: floor (dry or wet), wall (dry or wet), full shower (pan + walls + curb + niche + bench + optional ceiling), or freeze-thaw exterior.
  2. Enter dimensions: rooms (length × width) for floors; walls (length × height, less openings) for walls; pan/wall/door/niche/curb/bench dimensions for showers.
  3. Choose a tile material (porcelain, ceramic, glass, marble, travertine, slate, limestone, cement, mosaic, metal) and a size preset — or enter custom width/length/thickness. Check the polished box if it matters (forces unsanded grout on marble/glass/metal).
  4. Pick a layout pattern (straight stack, running bond, diagonal, herringbone, basketweave, Versailles, modular), grout joint width (1/16 to 3/8 inch), and installer experience (pro vs DIY).
  5. Select the substrate (concrete, plywood, cement board, Ditra, existing tile, or drywall for non-wet walls only).
  6. Open the advanced sections if relevant: waterproofing/uncoupling membrane (Ditra, Kerdi, RedGard, Hydro Ban, AquaDefense), heated floor cable + uncoupling, edge trim profiles (Schluter JOLLY/RONDEC/RENO-U/SCHIENE/QUADEC or bullnose), and TCNA EJ171 movement joints + leveling clips.
  7. Click Calculate: get tiles + boxes (rounded to one dye lot), thin-set bags by trowel, grout bags from the TCNA formula, membrane rolls or gallons, edge-trim sticks, silicone tubes for movement joints, plus installation notes and warnings.

How the TCNA grout formula and coverage rules work

The grout formula is: lbs/sq ft = ((L + W) / (L × W)) × joint width × joint depth × K. The K constant is the grout density in lbs/ft³ divided by 12 — K = 8.33 for Laticrete cement grouts (≈100 lb/ft³) and K = 9.00 for Custom Building Products Polyblend (≈108 lb/ft³), both back-verified from published coverage tables. The calculator uses K = 8.67 as a defensible mid-range. Thin-set coverage is driven by trowel notch size and tile dimension per TCNA F115/F116, then reduced 15% for wet areas (to hit the ANSI A108.5 95% coverage rule) and further reduced ~33% when embedding heated-floor cable. Always back-butter any tile with one edge ≥15 inches (large format / LFT) per ANSI A108.02-2023 §4.5.2, which also forces 33% max offset and ≥1/8" rectified joints.

Frequently Asked Questions

How much thinset do I need per square foot of tile?

Trowel size drives coverage, and trowel size is selected by tile dimension per TCNA F115/F116. Per the Mapei FAQ and confirmed against Custom Building Products and Laticrete: a 1/4"×1/4" square notch (for 4–8" tile) covers ~80–100 sq ft per 50 lb bag; 1/4"×3/8" (for 8–12") covers ~60–80; 1/2"×1/2" (for 12"+ / large-format) covers ~40–50. Reduce coverage by ~15% in wet areas to hit the ANSI A108.5 §3.3.2 95% coverage rule, and reduce another ~33% (i.e. budget ~1.5× material) when embedding radiant cable so the wire is fully encased. For a 200 sq ft floor of 12×24 porcelain in a dry interior: 200 / 45 ≈ 5 bags.

How much grout do I need for 12×24 tile?

Use the TCNA grout formula: lbs/sq ft = ((L + W) / (L × W)) × joint width × joint depth × K. K is the grout density (lbs/ft³) divided by 12 — K = 8.33 for Laticrete cement grouts (≈100 lb/ft³) and K = 9.00 for Custom Building Products Polyblend (≈108 lb/ft³). Both values are verified by back-calculation against the manufacturers' published coverage charts. For 12×24 tile at 3/16" joint × 3/8" depth: ((24+12)/(24×12)) × 0.1875 × 0.375 × 8.67 = ~0.076 lbs/sq ft. 200 sq ft = ~15 lbs of grout + 10% mix loss = ~17 lbs, which is one 25 lb bag. Aggregator densities of 0.1875 lbs/in³ (= 324 lbs/ft³) circulating online are about 3× too high — do not use.

What waste factor should I order for tile?

Laticrete's published baseline is 10% minimum for any tile job — and that is the floor, not the ceiling. Add to it: pattern complexity (running bond / brick: 10% pro / 13% DIY; diagonal: 15% / 18%; herringbone: 15% / 20%; Versailles or modular mosaic: 15% / 20%), large-format (any edge ≥15"): +5pp, natural stone: +5pp, polished tile: +2pp. So a DIY herringbone porcelain floor lands around 25%, while a pro straight-lay 12×12 floor lands at 10%. Always order on-spec or above — running short risks dye-lot mismatch (ANSI A137.1 §6.3 V0–V4) since manufacturers rarely guarantee a same-lot reorder.

Do I need modified or unmodified thinset over Ditra and Kerdi?

This is the most contested question in tile. Schluter's position (controlling for warranty purposes): use UNMODIFIED A118.1 dry-set to bond tile TO Ditra or Kerdi, because an impervious membrane sandwiched with impervious tile traps water in modified mortar and slows cure to 14–60 days per TCNA. To bond Ditra TO plywood you DO need modified A118.11. Schluter's own ALL-SET mortar (modified, meets A118.4T / .11 / .15) is permitted within the system. ANSI's position (A118.12 covers crack-isolation membranes used with modified mortar): modified mortar works, but the slow-cure issue is real. Bottom line: follow Schluter's manual to keep the system warranty, or use ALL-SET if you want one bag that does both layers.

What size trowel do I need for large-format tile (12×24 and bigger)?

Per TCNA F115/F116, any tile with one edge ≥15" is large-format (LFT) and triggers ANSI A108.02-2023 §4.5.2: medium-bed mortar (A118.15) once the embedded thickness exceeds 3/16", a 1/2"×1/2" or larger square-notch trowel, mandatory back-buttering, and 33% max offset. Substrate flatness tightens from 1/4" in 10 ft (standard) to 1/8" in 10 ft AND 1/16" in 2 ft. For 24"+ tile you'll typically run a 3/4"×3/4" square notch at ~30 sq ft per 50 lb bag. Back-buttering and the 95% wet-area coverage rule (ANSI A108.5 §3.3.2) effectively cut coverage another ~15%.

Can I use sanded grout with glass tile?

No. Sanded grout will scratch the surface of glass, polished marble, polished metal, and any honed or polished natural stone. Use unsanded grout (joints up to 1/8") or epoxy grout (ANSI A118.3) for wider joints. Glass tile also requires WHITE thinset (A118.4 white or A118.11 white) regardless of joint width, because glass is translucent and gray thinset will show through. For wider glass-tile joints (3/16"+), epoxy grout is the only correct answer.

How much RedGard or Kerdi do I need for a shower?

RedGard is sold by the gallon; coverage depends on which ANSI standard you're meeting. Per Custom Building Products TDS-104: for A118.10 waterproof rating, apply at 40 sq ft per gallon at 93 mil wet (47 mil dry), TWO coats — so a typical 80 sq ft shower needs 4 gallons. For A118.12 crack-isolation only, apply at 50 sq ft per gallon per coat, two coats. Schluter Kerdi sheet membrane comes in 108 sq ft rolls (3'3" × 33'); the same 80 sq ft shower needs 1 roll plus a roll of Kerdi-Band for seams. Showers require an A118.10 waterproofing membrane by code (IRC R702.4) — A118.12 crack-iso alone is NOT a waterproof rating.

Where do tile movement joints go and how often?

Per TCNA EJ171: interior floors get joints every 20–25 ft in each direction; exterior or wet areas every 8–12 ft. ALWAYS at the perimeter (where tile abuts walls, columns, curbs, dissimilar floors), at every change of plane (inside corners), and through any existing substrate control joints. Joint width minimum: 1/4" interior perimeter (never less than 1/8"), 3/8" exterior at 8 ft o.c., 1/2" at 12 ft o.c. Fill with 100% silicone meeting ASTM C920 Class 25 (Class 50 if calculated movement per ASTM C1193 × 1.25–1.5 safety factor exceeds 25% of joint width). A 10.1 oz tube covers about 24 LF at a 1/4" flat fill.

What's the difference between A118.4 modified thinset and A118.15 medium-bed?

Both are polymer-modified, but A118.15 (also called LHT or medium-bed) has a stiffer mix that holds up to 3/4" thickness without sagging — critical for large-format tile that needs back-buttering and a thicker bed to achieve 95% coverage on the inevitable lippage. Standard A118.4 sags at thicknesses over ~3/16" and is fine for tile under 12". The Custom Building Products LFT FAQ is explicit: "Use medium-bed mortar for tile with one edge greater than 15 inches when the embedded mortar thickness exceeds 3/16 inch." For 12×24 or anything bigger, switch to A118.15 — A118.4 alone leaves voids.

Do I need tile leveling clips, and how many per square foot?

Leveling clip systems (Raimondi RLS, Spin Doctor, Tuscan) are not optional for: large-format tile (any edge ≥15"), polished tile (lippage shows brutally under wall-wash lighting), plank patterns over 12" long (warpage), and 50% offsets of any large tile. Coverage per Raimondi guidance via Tools4Flooring: ~2 clips per square foot for 12×12 and larger, plus ~25% wedges. Plank tile gets ~2 clips per long joint + 1 per short joint. ANSI A108.02-2023 §4.4 caps lippage at 1/32" for joints 1/16"–<1/4" and 1/16" for ≥1/4" joints, plus the tile's own allowable warpage — clips are how you actually hit those tolerances.

What grout joint width should I use?

Tile manufacturer spec governs, but the practical defaults: rectified porcelain takes 1/16"–1/8"; pressed-edge ceramic typically 3/16"; large-format and natural stone need 3/16"–1/4" to absorb edge warpage; handmade or rustic tile often 3/8". ANSI A108.02-2023 sets a hard minimum of 1/8" for any rectified tile with one edge >15" (3/16" if calibrated), and the joint must increase by the tile's edge warpage. The grout type follows: sanded for joints ≥1/8" (ANSI A118.6 sanded); unsanded for joints up to 1/8" — except on glass, polished marble, and metal, which never take sanded grout regardless of joint width.