Tile Calculator
Work out how many tiles and how many boxes a job actually needs — for a floor, a wall, a shower, a backsplash or a whole multi-surface project — with the cut loss, the reserve and the box overage reported as three separate numbers instead of one vague word.
Layout loss, extra reserve and box overage are three different numbers here — and the layout one comes from simulating the tiles, not from a percentage.
Result
Verified Independent reverse check: 50 × 0.18580608 m² reproduces the net area 9.290304 m², and 50 whole tiles cover 9.290304 m². Packaging check: 10 × 6 = 60 ≥ 55, and 9 × 6 = 54 < 55.
- Net area to tile
- 100 ft²
- Tile face area
- 2 ft²
- Theoretical tiles
- 50
- Whole tiles for the surface
- 50
- Extra tile / reserve (10%)
- +5
- Purchase requirement
- 55
- tiles per box
- 6
- boxes to buy
- 10
- Purchased tiles
- 60
- Box overage
- +5
- Leftover tiles
- 10
- Leftover area
- 20 ft²
Where every tile goes
Layout loss, extra reserve and box overage are three different quantities. They are never added together under one word.
| Step | Value |
|---|---|
| A · Gross project area | 100 ft² |
| B · Openings / excluded area | none |
| C · Net project area | 100 ft² |
| D · Theoretical tile count | 50 |
| G · Whole tiles consumed | 50 |
| H · Calculated layout loss | not simulated in this mode — open the Tile Layout Planner |
| I · Extra tile / reserve | +5 (10%) |
| J · Purchase requirement | 55 |
| K · Boxes | 10 × 6 |
| L · Actual purchased tiles | 60 |
| Box overage (packaging only) | +5 tiles you did not choose and no cut caused |
| M · Leftover tiles | 10 |
| N · Leftover area | 20 ft² |
- Mode
- estimate
- Material format
- ceramic-porcelain-stone
- Internal length unit
- millimetres (single conversion from the entered unit)
- Internal area unit
- square metres (1 ft² = 0.09290304 m² exactly)
- Display
- ft² · auto rounding for display; internal values unrounded
- Gross area
- 100 ft²
- Openings
- none
- Net area
- 100 ft²
- Tile face area
- 2 ft²
- Method
- Area method with the tile face area (no layout simulated). Area source: 100 ft².
- Formula
tiles = area ÷ (tile width × tile height), then + reserve, then rounded up to whole boxes- Substitution
- 100 ft² ÷ 2 ft² = 50 → 50 whole tiles + 10% = 55 → 10 × 6 = 60
- Grout treatment
- Tile face area = width × height. The grout joint is not deducted from the tile.
- Extra tile / reserve
- 5 tiles (10%)
- Packaging
- 10 boxes × 6 = 60 tiles (box overage +5)
- Assumptions
- Tile face area is width × height; the grout joint is never subtracted from the tile itself.
- Dimensions are converted once to millimetres before any geometry runs; the display unit does not affect the result.
- No layout is simulated in this mode, so the count is area ÷ tile face area rounded up plus your reserve.
- Boxes are whole units: the purchase is rounded up to the next full box.
- Engine
- tile-engine v1.0.0 · state v1 · receipt 1.0.0
- Verification
- Verified — Independent reverse check: 50 × 0.18580608 m² reproduces the net area 9.290304 m², and 50 whole tiles cover 9.290304 m². Packaging check: 10 × 6 = 60 ≥ 55, and 9 × 6 = 54 < 55.
- Share id
- 46b2abb4befee9d2
Exports are tied to the mode that produces them: the layout SVG, PNG and cut list appear only when a layout has actually been simulated.
How many tiles do I need?
Three numbers answer it: the net area you are tiling, the face area of one tile, and how much extra you deliberately want. Divide the first by the second, round up to a whole tile, add the reserve, and only then convert to boxes. Doing it in that order matters, because each step has a different reason: the division is geometry, the round-up is because tiles do not split, the reserve is a decision, and the box rounding is the shop's constraint rather than yours.
Tile square footage formula
For a rectangular surface, square footage is length × width, with every opening you measured taken off. For a tile, square footage is width × height divided by 144 when the tile is measured in inches — a 12 × 24 in tile is 288 in², which is exactly 2 ft². Mixed units are safe here because every dimension is converted to millimetres before the multiplication and the area is converted back only for display.
Tile calculator formula
The whole chain, written out:
net area = gross area − Σ openings
tile face area = tile width × tile height
theoretical tiles = net area ÷ tile face area
purchase requirement = ⌈tiles consumed + reserve⌉
boxes = ⌈purchase requirement ÷ tiles per box⌉
purchased tiles = boxes × tiles per box
Worked through with the default on this page: 100 ft² ÷ 2 ft² = 50 tiles; 50 + 10% = 55; ⌈55 ÷ 6⌉ = 10 boxes; 10 × 6 = 60 tiles purchased, of which 50 go on the floor.
Does grout spacing change how many tiles I need?
In the area method, no. A 12 × 12 in tile covers 1 ft² whether it is set tight or with a 5 mm joint, and quietly reducing it to “0.97 ft² because of grout” is an invented adjustment that makes the answer look precise while making it wrong. What grout genuinely changes is the layout: the pitch from one tile to the next is tile width + joint, so wider joints shift where every course lands and therefore where the cuts fall. That is exactly where this calculator applies the joint — in the Tile Layout Planner, on the pitch — and nowhere else.
Waste, cuts and reserve are not the same thing
Four different quantities get collapsed into the word “waste”, and separating them is the single most useful thing a tile calculator can do.
- Tile coverage — the net area divided by the tile face area. Pure geometry, no allowance of any kind. This is the honest floor of the estimate.
- Calculated layout loss — the tile material cut off at walls, corners and obstacles and not put back on the surface. It comes from simulating the layout and measuring each cut tile, so it depends on the room, the tile and the pattern rather than on a rule of thumb. A 45° diagonal produces far more of it than a straight grid in the same room.
- Extra tile / reserve — the extra you choose to buy for breakage during setting and for repairs years later, when the dye lot has gone. It is a decision, not a measurement, which is why this calculator asks for it instead of assuming 10%.
- Box overage — the tiles you were forced to buy because boxes do not split. If you need 55 tiles and a box holds 6, you buy 60: five tiles of overage that nobody chose and no layout caused.
The result panel keeps all four apart, and the leftover figure tells you what actually stays in the garage: purchased tiles minus the tiles that went on the surface.
How to calculate floor tile
Measure the floor at its longest and widest, subtract anything that will not be tiled — an island base, a hearth, a fixed cabinet run — and divide by the tile face area. If the floor is L-shaped or interrupted, do not average it: add each rectangle as its own surface in Floors, Walls & Rooms, or draw the real outline in the Layout Planner, which handles L-shapes, several rectangles and arbitrary polygons with cutouts.
How to calculate wall tile
Tile each wall as its own surface: width × tiled height, minus the doors, windows and cabinets on that wall. Averaging openings across a room is what produces a shortfall on the wall that has none. A 4 × 2.5 m wall is 10 m²; a 0.9 × 2 m door removes 1.8 m², leaving 8.2 m² of tile.
Shower tile calculator
The Shower preset asks for the width, length and wall height, how many walls are tiled, and whether the floor is included, then reports shower wall area and shower floor area separately. That separation is the point: a shower floor is usually a small mosaic with a very different tile count and box quantity from the wall tile, so a single combined square-footage number cannot be ordered from. Add the door opening and a recessed niche and both are deducted from the wall they sit on.
Backsplash tile calculator
A backsplash is rarely one rectangle. Add a section per run — the main run behind the counter, the return by the window, the taller section behind the range — and deduct the window or any panel the range covers. The preset totals the net area, applies your reserve and converts to boxes; subway tile at 3 × 6 in means a large tile count, so the box quantity matters more than usual.
Tile layout patterns
Every pattern below is modelled geometrically — as a lattice plus a tile motif — and simulated tile by tile. A pattern that cannot be laid with a given tile shape is disabled rather than approximated.
| Pattern | Tile shapes |
|---|---|
| Straight / stacked | Rectangle, Square |
| Running bond 1/2 | Rectangle, Square |
| Running bond 1/3 | Rectangle, Square |
| Custom offset | Rectangle, Square |
| Diagonal 45° | Rectangle, Square |
| Herringbone 90° | Rectangle |
| Herringbone 45° | Rectangle |
| Checkerboard / alternating | Square |
| Honeycomb | Hexagon |
| Alternating triangle grid | Equilateral triangle |
Use Compare layouts to run the same room and the same tile through two or three of them. The differences you see are two complete simulations, with their own full and cut tile counts — not one simulation and a multiplier.
Common tile sizes
Load any row straight into the calculator.
| Dimensions | Area per tile | Tiles per ft² | Tiles per 10 ft² | Tiles per 100 ft² | Load |
|---|---|---|---|---|---|
| 3 × 6 in subway | 0.125 ft² | 8 | 80 | 800 | |
| 4 × 4 in | 0.11111111 ft² | 9 | 90 | 900 | |
| 6 × 6 in | 0.25 ft² | 4 | 40 | 400 | |
| 8 × 8 in | 0.44444444 ft² | 2.25 | 23 | 225 | |
| 12 × 12 in | 1 ft² | 1 | 10 | 100 | |
| 12 × 24 in plank | 2 ft² | 0.5 | 5 | 50 | |
| 16 × 16 in | 1.7777778 ft² | 0.5625 | 6 | 57 | |
| 18 × 18 in | 2.25 ft² | 0.4444 | 5 | 45 | |
| 24 × 24 in | 4 ft² | 0.25 | 3 | 25 |
How many boxes of tile do I need?
Divide the purchase requirement by the tiles per box printed on the carton and round up: boxes = ⌈requirement ÷ tiles per box⌉. The calculator checks both halves of that statement before it shows you a number — the boxes must cover the requirement, and one box fewer must not. Some tile is sold by coverage rather than count; the “Coverage from boxes” mode accepts either.
Tile cost calculator
Price the tile you actually buy. If you need 55 tiles and buy 10 boxes of 6, you pay for 60 — pricing the theoretical 50 understates the job by a fifth. Enter the price per tile, per box, per ft² or per m² and the cost engine applies it to the purchased quantity, then adds grout, adhesive, underlayment, waterproofing, delivery, disposal and any custom line you need. The breakdown shows the material/labour split and the cost per ft² and per m².
How to calculate installation cost
Match the labour basis to how you were quoted: a rate per ft² or per m², an hourly rate times hours, or a fixed price. Removal of the old floor is a separate line because it is priced separately in practice. No rate is pre-filled — a labour figure that is right in one city is wrong in the next one.
Grout calculator
Two methods, deliberately kept apart. Manufacturer coverage divides your area by the coverage printed on the package and rounds up to whole packages. Geometry estimate computes the joint volume directly: V = area × ((w + h) ÷ (w × h)) × joint width × joint depth, where (w + h)/(w × h) is the joint length per unit area of a rectangular grid. That gives a volume in litres. Turning litres into kilograms needs the product's density, so without one the calculator reports the volume and stops rather than inventing a weight.
Thinset / adhesive calculator
Divide the area by the coverage per bag and round up, with an optional allowance for the back-buttering and waste a real job involves. That coverage is a manufacturer figure that changes with the trowel notch, the substrate flatness and the tile back profile, so it is an input here. Backer board and waterproofing work the same way: sheet size or per-coat coverage from the product, never a stored constant.
Worked examples
- 10 × 12 ft floor with 12 × 24 in tile — Room dimensions instead of a known area.
- 100 ft² with 12 × 24 in tile — The documented default: 50 tiles, 55 with reserve, 10 boxes.
- 60 ft² backsplash with 3 × 6 in subway tile — Small tile, larger reserve, big box quantity.
- Shower walls + shower floor, separate tiles — Three tiled walls at 7 ft plus a mosaic floor.
- Bathroom wall with a door opening — 4 × 2.5 m wall minus a 0.9 × 2 m door = 8.2 m².
- 12 × 12 in tile with a 10% reserve — 100 ft² → 100 tiles → 110 with the reserve.
- Herringbone layout, simulated tile by tile — The same room laid at 90° herringbone.
- Diagonal 45° layout on an L-shaped room — Concave outline plus a rotated field — every cut counted.
- Boxes plus total project cost — Tile priced per box, labour per ft².
Roof tile is a different calculation
Roof tile estimation uses different geometry from floor and wall tile because pitch, exposure, headlap and roof geometry affect the result. This calculator deliberately does not produce a roof tile figure — a wrong number would be worse than no number.
Methodology & verification
Five modes run on one dedicated engine stack (tile-engine v1.0.0). Every length is parsed once and converted to millimetres before any geometry runs, and areas are carried in square metres, so mixing feet, inches, millimetres and metres can never apply a conversion factor twice. The tile face area is width × height: the grout joint is never subtracted from the tile itself. Joint width instead sets the layout pitch (tile width + joint, tile height + joint), where it legitimately changes courses, offsets and cuts. The Tile Layout Planner is a real simulation, not a waste percentage: every pattern is modelled as a lattice plus a tile motif, each candidate tile is clipped against the tiled region with Sutherland–Hodgman convex clipping, and its intersection area is measured to classify it as full, cut or unused. Seven quantities are kept separate throughout — net project area, theoretical tile count, calculated layout loss, extra reserve, purchase requirement, box overage and leftover stock — because collapsing them into one word ("waste") is what makes most tile estimates wrong. Materials and cost contain no stored coverage figures, densities or average prices: every one of those is an input, because they vary by product, trowel, joint, country and contractor. Each result ships a calculation receipt with the inputs, conversions, formula, substitution, assumptions, engine version and a fail-closed verification — if an invariant breaks, the page shows a structured error instead of a plausible-looking number.
- Unit basis: exact international factors (1 in = 0.0254 m, 1 ft = 0.3048 m, 1 ft² = 0.09290304 m²) from the shared unit registry; every length is converted to millimetres exactly once before any geometry runs.
- Grout treatment: tile face area = width × height, always. The joint sets the layout pitch (tile + joint) and nothing else.
- Layout algorithm: each pattern is a lattice (u, v) plus a tile motif. Every candidate tile is clipped against the tiled region with Sutherland–Hodgman convex clipping and its intersection area is measured; a placement is FULL within 1e-9 of a tile face, CUT below that, and UNUSED at or under the same tolerance.
- Layout verification: the gap-free lattice cells are clipped against the region as well, and their areas must reproduce the region area to within 1e-7 of it. That proves the pattern really tiles the plane and that no placement was missed — if it fails, the page shows a structured error instead of a layout.
- Packaging verification: boxes × tiles per box must be at least the purchase requirement, and one box fewer must be less than it. Both are checked before a box count is displayed.
- Invariants: non-negative areas, net ≤ gross, non-negative counts, an integer box count, purchased = boxes × tiles per box, purchased ≥ requirement and leftover ≥ 0 are asserted on every result; a violation produces an error, never a plausible-looking number.
- Offcut reuse: not assumed. No nesting or offcut optimiser is implemented, and the cut list says so rather than implying one.
- No stored commercial values: grout coverage, grout density, adhesive coverage, sheet sizes, prices, labour and disposal rates are all inputs.
Assumptions
- The tile face area is width × height; grout joints are modelled as layout pitch, never as a reduction of the tile itself.
- Every dimension is normalized to millimetres before any geometry runs, and the display unit never changes the physical result.
- Openings are the dimensions you enter — no average door, window, niche or cabinet size is assumed anywhere.
- Whole tiles and whole boxes are rounded up: you cannot buy 0.4 of a tile or 0.7 of a box.
- Offcut reuse is not assumed: a piece cut from one tile is never counted as covering another gap, because no nesting optimiser is implemented.
- Grout coverage, adhesive coverage, grout density, sheet sizes and every price are inputs taken from your product and your quote.
Author: Ugo Candido · Last reviewed: · Engine: tile-engine v1.0.0 · Review status: No independent third-party review. The author is responsible for the methodology; correctness is enforced by the engine's golden reference vectors, automatic invariants, the layout closure verification and the dedicated renderer test suite. Every calculation runs in your browser; nothing you type is sent to a server. See the public changelog.
Limitations
- Nominal vs actual tile dimensions: a tile sold as 12 × 24 in is often slightly smaller. Measure a real tile and enter the actual size when the fit matters.
- Rooms are rarely square. A wall that runs out of plumb, a floor that is out of square or a bowed substrate adds cuts this geometry cannot see.
- Field conditions — thresholds, drains, pipe penetrations, uneven substrate, tile sorting and shade variation — are not modelled.
- The grout joint here is the field joint between tiles. Perimeter joints, movement joints and expansion joints are a specification decision and are not calculated.
- Offcut reuse is not assumed and no nesting optimiser is implemented, so the cut list groups required pieces without claiming to source them from earlier offcuts.
- Grout density and packaged yield are product properties. Without a density the geometry method reports a joint volume and stops rather than inventing a weight.
- Adhesive coverage depends on the trowel notch, the substrate flatness and the tile back profile; only the figure you enter is used.
- Labour rates, removal rates, delivery and disposal vary by country, city, season and contractor — no average is stored or suggested.
- This is a planning estimate. Confirm quantities with your installer's own measurement before ordering, especially for a dye-lot-sensitive tile.
Frequently asked questions
How many tiles do I need?
Divide the net area you are tiling by the face area of one tile, round up to a whole tile, then add your reserve. For 100 ft² with a 12 × 24 in tile that is 100 ÷ 2 = 50 tiles, or 55 with a 10% reserve. Boxes come last, because they only sell whole.
How do I calculate tile square footage?
Multiply length by width for each surface, subtract every opening you measured, and add the surfaces together. Feet-and-inches input works directly: 10 ft 6 in × 12 ft is 10.5 × 12 = 126 ft².
How many 12x24 tiles do I need for 100 square feet?
A 12 × 24 in tile is 288 in², which is exactly 2 ft². So 100 ft² needs 50 tiles before any reserve, 55 with a 10% reserve, and 10 boxes if the box holds 6 — 60 tiles purchased.
How much extra tile should I buy?
There is no universal number, which is why this calculator asks instead of assuming. A simple straight layout in a square room needs little; a diagonal or herringbone layout, a room with many cuts, or a tile you may never find again all argue for more. Simulate the layout to see the real cut loss, then choose the reserve on top of it.
Does grout spacing affect how many tiles I need?
Not in the area method: a 12 × 12 in tile is 1 ft², grout or no grout, and pretending it is 0.97 ft² is a made-up adjustment. Joints do matter in a real layout, where they set the pitch between tiles and therefore change where the cuts fall — which is exactly where this calculator applies them.
How do I calculate tiles for a floor?
Measure the floor length and width, subtract anything that will not be tiled, and divide by the tile face area. For an L-shaped or interrupted floor, add each rectangle as its own surface, or draw the outline in the Layout Planner.
How do I calculate tiles for a wall?
Multiply the wall width by the tiled height, then subtract the doors, windows and cabinets you measured. Tile each wall as its own surface so the openings land on the right wall instead of being averaged across the room.
How do I calculate shower tile?
Enter the shower width, length and wall height, choose how many walls are tiled, and say whether the floor is included. The result separates shower wall area from shower floor area, because a shower floor is usually a different, smaller tile with its own box quantity.
How do I calculate backsplash tile?
Measure each run of counter separately: run width × backsplash height. Subtract windows and any section the range or cabinets cover. The Backsplash preset adds as many sections as the kitchen needs and totals them.
How many tiles are in a box?
It varies by tile size and manufacturer, and it is printed on the box along with the coverage. Enter that number and the calculator converts the tile requirement into boxes, rounding up, and shows the overage the rounding created.
How do I calculate tile cost?
Price the tile you actually buy, not the theoretical count — you pay for whole boxes. Enter the price per tile, per box, per ft² or per m², and the cost engine applies it to the purchased quantity and adds the materials and labour you entered.
How do I calculate installation cost?
Choose a labour basis that matches your quote: a rate per ft² or per m², an hourly rate times hours, or a fixed price. Add removal of the old floor, delivery and disposal as separate lines so you can see the material/labour split rather than one lump sum.
Does a diagonal layout require more tile?
Usually yes, because a 45° field meets every wall at an angle and almost every perimeter tile is cut. How much more depends on the room and the tile, so the Compare layouts table runs the same room twice — straight and diagonal — and reports both simulations instead of quoting a rule of thumb.
Does herringbone require more tile?
Typically yes: the zigzag meets the walls in angled pieces and the perimeter needs many part tiles. The calculator simulates herringbone at 90° and 45° as real geometry, so the extra comes from counted cut tiles rather than an assumed percentage.
Can I subtract doors and windows?
Yes — add each opening to the surface it sits on, with its own width, height and quantity. Every deduction is itemised in the calculation receipt, and an opening larger than the surface is rejected as an error rather than quietly clamped to zero.
How do I calculate grout?
Two different ways, kept apart. The manufacturer method divides your area by the coverage printed on the package. The geometry method computes the joint volume from tile size, joint width and joint depth; without a density it reports a volume, because turning volume into kilograms needs a product property this calculator will not invent.
How much thinset do I need?
Divide the area by the coverage per bag for your trowel notch, then round up. That coverage is a manufacturer figure that changes with the notch, the substrate and the tile back, so it is an input here — there is no universal bags-per-square-foot number.
Can I calculate coverage from tiles I already own?
Yes. Switch the estimator to “Area covered” and enter the tile count, or to “Coverage from boxes” and enter the boxes with either the tiles per box or the coverage printed on the box.
What is the area of a 12×24 tile?
288 square inches, which is 2 ft² or about 0.1858 m². That means one tile covers 2 ft², half a tile per square foot, and 50 tiles cover 100 ft².
Is this calculator suitable for roof tile?
No. Roof tile estimation uses different geometry from floor and wall tile because pitch, exposure, headlap and roof geometry affect the result, and this calculator deliberately does not produce a roof tile figure rather than produce a wrong one.