Tile Calculator
This tile calculator tells you how many tiles to buy for a floor, wall, backsplash, shower or ceiling. It works out the tile square footage, counts the joints, adds extra for cuts, rounds up to whole boxes and estimates the grout, the thinset and the installation cost. Tap the i button beside any field for an explanation.
Quick answer: tiles needed = area ÷ the area of one tile (with its joint), plus about 10% extra. A 12 × 10 ft floor with 12 × 24 inch tiles needs 65 tiles, which is 9 boxes of 8.
Tile calculator: enter your surface and tile
Example values are loaded so you can see a result straight away. Change any field and the numbers update.
1. Choose your units
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2. What are you tiling?
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3. Tile and layout
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4. Prices and materials
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Where the money goes
Each bar is one part of the total. Labour is orange. Prices are the examples you can edit.
Tiles needed by layout
Grout needed by joint width
Estimates for planning only. Prices shown are examples you can edit, not quotes. Measure the surface yourself, check the box label for the real tiles per box, and follow the tile and setting-material makers’ instructions. See our Disclaimer.
How the tile calculator works
Buying tile is a game of small numbers that add up. Count too few and you are back at the store with a different dye lot. Count too many and you are paying for boxes you will never open. A good estimate needs the area, the size of the tile, the joint between tiles, and an allowance for the cuts you will make.
This tile calculator takes those inputs and does the whole chain for you. It finds the area to tile, subtracts any openings, counts the tiles with the grout joint included, and adds your extra allowance. It then rounds up to whole boxes, tells you how many spare tiles you will own, and estimates the grout, the thinset and the cost. The two charts show how layout and joint width change the numbers.
How to calculate square feet for tile
Everything starts with the area, and the method is the same whether you call it a tile square footage calculator or a tile sq ft calculator. Measure in feet, multiply, and take off what you will not tile:
- Measure the length and width of the surface. For a wall or backsplash, use the width along the wall and the height you will tile.
- Multiply them to get square feet. A 12 × 10 ft room is 120 sq ft.
- Add rooms together if you are tiling more than one. Split an L-shaped room into rectangles and add them.
- Subtract the openings. Doors, windows, a tub or a niche are not tiled, so take their area off.
If your measurements are in inches, divide by 144 to turn square inches into square feet. If you already know the total, choose “I know the total area” in the calculator and enter it directly.
How many tiles do you need?
Once you have the area, divide it by the area one tile takes up on the surface. That is the part many quick calculators skip. A tile does not cover only its own face. It also covers half of the grout joint on each side, so the real footprint is (width + joint) × (length + joint).
For our 120 sq ft floor with 12 × 24 inch tiles and a 1/8 inch joint, one tile covers 12.125 × 24.125 = 292.5 square inches. The floor is 120 × 144 = 17,280 square inches, so it holds about 59.1 tiles. That is 60 tiles with no extra, and 65 once you add 10% for cuts.
The table shows how the count changes with area and tile size, using a 1/8 inch joint and 10% extra.
| Area to tile | 12 × 12 in | 12 × 24 in | 18 × 18 in | 24 × 24 in |
|---|---|---|---|---|
| 50 sq ft | 54 | 28 | 25 | 14 |
| 100 sq ft | 108 | 55 | 49 | 28 |
| 150 sq ft | 162 | 82 | 73 | 41 |
| 200 sq ft | 216 | 109 | 97 | 55 |
Bigger tiles mean fewer pieces, but each cut wastes more of a large tile.
How much extra tile should you buy?
You will cut tiles at every wall, around every pipe and at every corner. Some pieces will crack, and some cut-offs will be too small to reuse. Many guides suggest about 10% extra for a straight layout, and about 15% for diagonal layouts. Herringbone, small tiles and awkward room shapes call for more, and guides put those anywhere from 10% to 25%.
The calculator sets a starting allowance when you pick a layout, and you can type over it. For a 120 sq ft floor with 12 × 24 inch tiles, the layout alone changes the order like this:
| Layout | Allowance used | Tiles for 120 sq ft | Boxes of 8 |
|---|---|---|---|
| Straight (grid) | 10% | 65 | 9 |
| Offset (brick) | 10% | 65 | 9 |
| Diagonal | 15% | 68 | 9 |
| Herringbone | 20% | 71 | 9 |
Treat these as starting points. A simple rectangular room can sit near the low end, while angled walls or a centred pattern need the high end.
Shower tile calculator: three walls and a niche
A shower or tub surround is easiest to measure one wall at a time. Choose the shower option in the calculator and enter the back wall width, the depth of the side walls, and how high the tile will go. The calculator counts the back wall once and the side walls twice.
Take a 5 ft back wall with two 2.5 ft side walls, tiled to 7 ft. That is (5 + 2 × 2.5) × 7 = 70 sq ft. A 2 sq ft niche takes it down to 68 sq ft. With 3 × 6 inch subway tiles and a 1/8 inch joint, that surface holds about 511.6 tiles, so you would order 563 with 10% extra, which is 5 boxes of 120.
Two things are easy to forget. The niche has its own sides and back that also need tile, and a shower floor is a separate surface that often takes a different, smaller tile. Run the floor as its own calculation.
Backsplash and wall tile
A backsplash is a small, fussy job, so the extra allowance matters. Measure the length of the counter and the height from the counter to the bottom of the cabinets, then subtract any window or outlet cut-outs you will not tile around. A 30 sq ft backsplash in 3 × 6 inch subway tile needs about 225.7 tiles, or 249 with 10% extra, which is 3 boxes of 120.
Use the rectangle option and enter the length and the height. Small tiles lose less on each cut but bring many more joints, and the grout chart shows how much that adds.
How to calculate ceiling tiles
Ceiling tiles use the same idea with one change. Drop-ceiling panels sit edge to edge in a grid, so there is no grout joint to count. Set the joint width to 0, pick a panel size such as 24 × 24 inches, and enter the ceiling area.
A 12 × 10 ft ceiling is 120 sq ft. A 2 × 2 ft panel covers 4 sq ft, so the room holds 30 panels, and 33 with 10% extra. Ceiling grids are often centred so the border panels match on opposite walls, and those panels are cut, so count them in your layout for an exact figure.
How much grout do you need?
Grout fills the joints, so the amount depends on how much of the surface is joint and how deep the joints are. The calculator finds the share of the surface that is joint, which is 1 minus the area of the tile faces divided by the area of the tile plus the joint. It multiplies that by the tile thickness to get the volume, then by an assumed 100 lb of grout per cubic foot, with 10% extra for waste.
The result for our example is about 6.4 lb, so one 10 lb bag is enough. The table shows how tile size and joint width drive it for 100 sq ft of 3/8 inch tile.
| Tile size (3/8 in thick, 100 sq ft) | 1/16 in joint (lb) | 1/8 in joint (lb) | 1/4 in joint (lb) |
|---|---|---|---|
| 4 × 4 in | 10.5 | 20.5 | 39.3 |
| 12 × 12 in | 3.6 | 7.1 | 13.9 |
| 12 × 24 in | 2.7 | 5.3 | 10.5 |
| 24 × 24 in | 1.8 | 3.6 | 7.1 |
Small tiles and wide joints use much more grout. Moving from a 1/8 inch joint to a 1/4 inch joint roughly doubles the amount. This is an estimate, not a coverage chart, so check the maker’s figures for your product, especially for textured tile or deep joints.
Thinset and how many boxes to buy
Thinset is the mortar under the tile. How far a bag goes depends on the trowel, the tile and the surface, so the calculator asks for the coverage printed on your bag. It adds 10% for waste and rounds up to whole bags. With 60 sq ft per bag as an example, 120 sq ft needs 3 bags.
Tile comes in boxes, so the order is always whole boxes. The calculator divides your tile count by the tiles in a box, rounds up, and then shows the spare tiles you will own. Ours is 9 boxes of 8, which is 72 tiles and 12 spare.
How much does tile installation cost?
Used as a tile installation cost calculator, this page builds the cost from the tile you buy, the grout, the thinset and the labour. Because tile is sold by the box, you pay for every tile in the boxes, including the spares. That is why the calculator prices the tile you will own and not just the tile you need.
The table shows the example floor with placeholder prices. They are not quotes, so replace them with your own shelf prices and installer estimate.
| Item | Quantity | Example price | Cost |
|---|---|---|---|
| Tile | 9 boxes (72 tiles) | $4.00 per sq ft | $576 |
| Grout | 1 bag of 10 lb | $18 per bag | $18 |
| Thinset | 3 bags | $32 per bag | $96 |
| Labour | 120 sq ft | $8 per sq ft | $960 |
| Total | $1,650 |
On these prices the total is $1,650, which is $13.75 per square foot, with $576 in tile and $960 in labour. Set the labour price to 0 to see a do-it-yourself figure. Cost estimates do not include demolition, floor preparation, trim, sealer or waterproofing, which can matter a lot on a real job.
Choosing a tile size and joint width
Size changes more than the look. Larger tiles have fewer joints, so they need less grout, but they leave bigger offcuts at the edges and are heavier to handle. Smaller tiles follow curves and tight spaces more easily and are common on shower floors and backsplashes, at the cost of more joints and more grout.
Joint width is a design and a product choice, so follow the tile maker’s guidance on the minimum joint for your tile. The calculator accepts any joint from 0 up to 1 inch, so you can compare options before you commit.
Before you buy tile
- Measure twice. Check each wall, because rooms are rarely square.
- Read the box. It gives the tiles per box and the coverage, and the size on the label may differ from the real size.
- Match the lot. Buy all the boxes together and compare the lot numbers, since shade can differ between runs.
- Plan the layout. Decide where the pattern starts, because a centred layout changes the cuts at the edges.
Common mistakes when ordering tile
- Ignoring the joint. Dividing by the tile face alone makes the count a little high, and the gap grows with wider joints.
- Forgetting the extra. An order with no allowance runs short at the last row.
- Not rounding to boxes. You cannot buy part of a box, so the real order is always a whole number of boxes.
- Not subtracting openings. A large window or a tub can remove a lot of area from a shower.
This page is a planning tool and does not replace the instructions from the tile and setting-material makers. For waterproofing, heated floors or structural questions, talk to a qualified installer.
Tile calculator FAQ
What if my room is not a simple rectangle?
Split it into rectangles, work out the area of each, and add them together. For an L-shaped room, that is two rectangles. Enter the total in the total area option, or run each part separately if you want different tiles in each.
How many tiles do I need for a 12 × 10 ft floor?
With 12 × 24 inch tiles, a 1/8 inch joint and 10% extra, a 120 sq ft floor needs 65 tiles. That is 9 boxes of 8, which leaves 12 spare tiles.
How much extra tile should I buy?
Many guides suggest about 10% for a straight layout and about 15% for diagonal layouts, with herringbone and small or awkward rooms needing more. The calculator sets 10%, 10%, 15% and 20% by layout, and you can type your own figure.
Does the joint width change how many tiles I need?
Yes, a little. Every tile uses up its own area plus half a joint on each side, so wider joints cover more floor per tile. On our example floor, a 1/4 inch joint needs 64 tiles instead of the 65 at 1/8 inch.
How many tiles do I need for a shower?
Add up the area of each wall you will tile, subtract niches and windows, and divide by one tile. A 5 ft back wall with two 2.5 ft side walls, 7 ft tall, is 70 sq ft. Take off a 2 sq ft niche and 3 × 6 inch subway tiles need about 563 with 10% extra.
How many 2 × 4 ft ceiling panels do I need?
Each panel covers 8 square feet, so divide the ceiling area by 8. A 12 × 10 ft ceiling needs 15 panels, or 17 with 10% extra. Choose the 24 × 48 inch size and set the joint to 0.
How much grout does a shower need?
Small tiles mean many joints, so a shower can need more grout than a larger floor. Our 68 sq ft shower with 3 × 6 inch tiles and a 1/8 inch joint comes to about 13.9 lb of dry grout with 10% extra, which is 2 bags of 10 lb.
How many boxes of tile do I need?
Divide the tiles you need by the number of tiles in a box and round up. Retailers sell tile by the box, so you always buy whole boxes. The calculator shows the boxes and the spare tiles you will own.
How much should I budget to tile a 120 sq ft floor?
It depends on the tile, the layout, the floor underneath and local labour rates, so use your own prices. At the example prices in the calculator, a 120 sq ft floor comes to about $1,650, or $13.75 per square foot including labour.
Do I subtract the tub, window or door from the tile area?
Yes. Measure the full surface, then subtract the parts you will not tile, such as a tub, window or door opening. Put the total in the area to subtract field, and the calculator takes it off before it counts tiles.
Should I buy all my tile at the same time?
It is wise to. Tiles can differ in shade between production runs, so buy all the boxes together and check that the lot numbers match. Keep the spare tiles for future repairs, because the same tile may not be sold later.
Sources and further reading
The area and tile counts are plain geometry. The extra allowances follow the common guidance in the articles below, and the grout method and its 100 lb per cubic foot default follow the approach on the Omni page. Prices are editable examples.
- CLE Tile, how much extra tile to buy (about 10% for straight layouts and 15% for diagonal layouts)
- Flooring Clarity, how much extra tile for a herringbone pattern (10% to 20% for herringbone)
- Omni Calculator, grout calculator (tile-to-joint ratio and the default grout density)
- Tile Council of North America (installation standards for ceramic, glass and stone tile)
Product details vary by maker, so confirm figures on the packaging.
Plan the rest of the project
Tiling a new floor? The flooring calculator covers other floor types, the square footage calculator measures odd-shaped rooms, and the paint calculator sizes the walls above your tile. Browse the flooring calculators hub for more tools, or price a slab base with the concrete slab cost calculator.