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Tile Calculator

Everyday

Calculate tiles needed for any room with custom tile size, wastage allowance, and box count. Enter room dimensions to get exact quantities instantly.

Reviewed by the thecalcu.com team · Last updated July 2, 2026

Room Dimensions
12 ft
1100
10 ft
1100
Tile Size
12 in
148
12 in
148
Wastage Allowance
12 tiles
150
Tiles Needed
—
incl. 10% wastage allowance
Boxes
—
Base Tiles
—
Room Area
—
Wastage Tiles
—
Common Tile Sizes
12×12 in — Standard floor
18×18 in — Large floor
24×24 in — XL format
4×8 in — Subway / wall

What is a Tile?

The Tile Calculator works out exactly how many tiles a room needs, based on the room's dimensions, the size of the tile you've chosen, a wastage allowance for cuts and breakage, and how many tiles come in each box. Tiling jobs are notoriously easy to miscount by hand, order too few and you're stuck mid-project waiting on a possibly mismatched restock, order too many and you've overspent on material that's often non-returnable once opened.

The calculator takes room dimensions in feet, since that's how most people describe room size, and tile dimensions in inches, since that's how individual tiles are typically labeled. It doesn't stop at a raw tile count either, it converts that into a box count, since tiles are sold by the box, not individually, and "you need 87 tiles" isn't nearly as actionable as "you need 8 boxes." The Square Footage Calculator is a natural companion if you need to confirm room area first, and the Concrete Calculator helps if you're also pouring the subfloor underneath.

Why Use a Tile Calculator?

Tile is expensive to guess wrong on. Once a box is opened, most retailers won't take it back, and dye lots vary between production runs, so if you underorder and need to go back for more weeks later, there's a real chance the new tiles won't match exactly. Getting the count right up front avoids both the financial waste of overordering and the aesthetic risk of a mismatched second batch.

The wastage adjustment matters more than people expect. A straight grid layout wastes relatively little, but a diagonal or herringbone pattern chews through significantly more material in offcuts, sliding the wastage percentage from 10% to 20% shows you exactly how much extra that stylistic choice costs in tile count before you commit to it. And running the numbers for two tile sizes side by side, say 12x12 versus 24x24 inches, makes it easy to compare material requirements before finalizing a design decision.

How to use this Tile calculator

  1. Measure your room and enter the values into Room Length and Room Width, in feet, decimal fractions are fine (11.5 ft for 11'6").
  2. Enter your chosen tile's dimensions into Tile Length and Tile Width, in inches, converting from millimeters by dividing by 25.4 if needed.
  3. Set Wastage based on your layout complexity, 10% for a simple grid, 15% for rooms with obstacles or a diagonal pattern, 20% for herringbone or intricate designs.
  4. Enter Tiles per Box exactly as printed on the box label for your chosen tile.
  5. Read the Tiles Needed and Boxes Needed results, and round your actual order up slightly if you want a buffer for future repairs.

Common Mistakes to Avoid

Skipping the wastage allowance entirely is the most costly mistake, ordering the exact bare-minimum tile count leaves zero room for a bad cut, a dropped tile, or a miscount, and any of those means a return trip that might not even get you the same dye lot. Underestimating wastage for a diagonal or patterned layout is a related version of the same problem, these layouts genuinely do produce more offcuts than a simple grid, and a 10% allowance calculated for a straight lay won't cover it.

Entering room dimensions in the wrong unit, feet instead of the tile's inches, or vice versa, throws the whole calculation off by a large factor, so double-check which field expects which unit before you rely on the output. And forgetting to buy a few tiles beyond even the wastage-adjusted total, as a long-term repair reserve, is a mistake that only becomes obvious years later when a single cracked tile can't be matched to a discontinued batch.

Formula & Methodology

Room Area (sq ft) = Room Length × Room Width

Tile Area (sq ft) = (Tile Length in inches ÷ 12) × (Tile Width in inches ÷ 12)

Base Tiles = ceil(Room Area ÷ Tile Area)

Tiles Needed = ceil(Base Tiles × (1 + Wastage % ÷ 100))

Boxes Needed = ceil(Tiles Needed ÷ Tiles per Box)

Wastage Tiles = Tiles Needed − Base Tiles

Worked example: a bedroom measuring 14 x 12 ft, tiled with 24x24 inch tiles that come 4 per box, with a 10% wastage allowance.

- Room Area = 14 × 12 = 168 sq ft
- Tile Area = (24 ÷ 12) × (24 ÷ 12) = 2 × 2 = 4 sq ft
- Base Tiles = ceil(168 ÷ 4) = 42 tiles
- Tiles Needed = ceil(42 × 1.10) = ceil(46.2) = 47 tiles
- Boxes Needed = ceil(47 ÷ 4) = 12 boxes (48 tiles)
- Wastage Tiles = 47 − 42 = 5 tiles

The buyer should pick up 12 boxes (48 tiles total), which leaves a spare tile beyond the calculated wastage for future repairs.

Quick Reference

Wastage Level When to Use
10% Simple rectangular room, straight grid layout
15% Rooms with obstacles, fixtures, or a diagonal layout
20% Herringbone or other complex patterns

For confirming irregular or multi-section room areas before running this calculator, see the Square Footage Calculator or the more general Area Calculator.

Frequently Asked Questions

A 10x10 ft room covers 100 square feet, and a 12x12 inch tile covers exactly 1 square foot, so the base count is 100 tiles. Add a standard 10% wastage allowance for cuts and breakage and you'd order 110 tiles, round up to 10 boxes if they come 12 per box.
Divide total floor area by the area of one tile, then add your wastage percentage. A 15x12 ft room is 180 sq ft, and an 18x18 inch tile covers 2.25 sq ft, so 180 ÷ 2.25 = 80 tiles before wastage, or roughly 88-92 tiles after a 10-15% allowance.
10% covers a straightforward rectangular room laid in a simple grid pattern. Bump that to 15% for rooms with lots of obstacles, columns, alcoves, fixtures, or a diagonal layout, and go as high as 20% for herringbone or other complex patterns that generate more offcuts.
It varies by tile size and manufacturer, so always check the box label rather than assuming. Large-format tiles (24x24 inches or bigger) often ship 4-6 per box, while smaller mosaic or wall tiles can pack 40-80 per box, enter your actual per-box count for an accurate order quantity.
Split the space into regular rectangular sections, calculate tile count for each one separately, then add the totals together. Apply your full wastage allowance to the combined number, since irregular layouts generate more cuts than a simple rectangle would.
Yes, always pick up a few extra from the same production batch, on top of what the wastage percentage already covers. Tile color and texture can shift slightly between manufacturing runs, and if a tile cracks years later, matching an out-of-production batch can be next to impossible.
Smaller tiles, 12x12 or 16x16 inches, tend to need less cutting around fixtures in tight bathrooms and small spaces under 100 sq ft. Larger 24x24 inch tiles can visually open up a small room but typically produce more wastage from cuts along the edges.
Divide by 25.4 to get inches from millimeters (or by 2.54 for centimeters). A 600mm tile becomes 600 ÷ 25.4 = 23.62 inches, enter that decimal value directly into the calculator, which accepts fractional inches without any issue.
No, it calculates purely from tile dimensions, without subtracting the grout gap between tiles. In practice that gap, typically 1/16 to 1/8 inch, is negligible relative to tile size, and the wastage allowance more than absorbs any tiny discrepancy it might introduce.
Multiply your box count by the price per box for material cost, then add labor, installation typically runs a set rate per square foot depending on tile size and pattern complexity, plus adhesive and grout, usually priced per square foot as well. The room area this calculator outputs is the base number for all three of those estimates.
The math is identical for walls and floors, it's just area divided by tile area either way. Just make sure your 'room length' and 'room width' inputs represent the actual wall dimensions you're tiling, not the floor footprint, if you're doing a backsplash or shower surround.
You'll get the bare minimum tile count with zero buffer for cuts, breakage, or mistakes, which only makes sense if you're doing a rough material estimate rather than an actual purchase order. For any real project, even a careful installer should budget at least 5-10% to avoid a mid-job trip back to the store.
Also known as
tile area calculatorfloor tiles calculatorwall tiles calculatortiles neededtiles quantity calculatorhow many tiles