Waste, walls, cut outs, thinset and trimYour own waste %, floor or wall, openings, trowel, bullnose
More costs and pricingGrout and thinset bags, leveling, outdoor work, trim, other fees
See full breakdown
Measure the space and multiply length × width to get square feet, then divide by the area of one tile. A 12 × 12 in tile covers 1 sq ft, so a 120 sq ft floor needs about 118 tiles once the 1/8 in grout joints are counted. Add 10% for a straight layout or 15% for diagonal, herringbone or a room full of corners, then divide by the tiles in a box and round up to whole boxes.
How many tiles do I need? The formula
Every answer to how many tiles do I need comes from the same five steps. The calculator runs them in this order, with the grout joint counted as part of each tile.
| What you enter floor or wall | How it is worked out imperial shown, metric works the same | |
|---|---|---|
| Area to tile | Length and width (or the total area), surfaces and cut outs | Length × Width × Surfaces, minus cut outs |
| Space per tile | Tile size and grout joint width | (Tile length + joint) × (Tile width + joint) ÷ 144 |
| Tiles for the area | Nothing new | Area ÷ Space per tile |
| Tiles to buy | Layout pattern or your own waste % | Tiles for the area × (1 + waste %), rounded up |
| Boxes | Tiles per box | Tiles to buy ÷ Tiles per box, rounded up to a whole box |
| Tile cost | Price per box | Boxes × Price per box |
Worked example: a 12 × 10 ft floor in 12 × 12 in tile, 1/8 in joints, straight layout, 11 tiles per box
When to use this tile calculator
Use it whenever a floor, wall, shower or backsplash is about to be tiled and you want the order settled before anything is bought or bid.
- Before buying tile: order once, from one production lot, and skip the second trip.
- Pricing the materials: enter the box price and the tile cost appears next to the box count. The Price the install tab then adds grout, thinset, labor and prep, so the material budget and the full job sit side by side before you commit.
- Comparing sizes and patterns: switch from 12 × 12 to 24 × 24, or from straight to herringbone.
- Checking a contractor bid: a bid that allows 20% overage on a plain rectangular kitchen is padding the order. Run the room here and compare the tile allowance on the bid with what the layout actually needs.
- Walls and backsplashes: pick Wall, enter width and height, and subtract the window.
- Partial repairs and remodels: replacing a cracked section or one wall of a shower uses the same math on a smaller area. Measure only the part being replaced, and keep a few spares, since a discontinued tile is hard to match later.
- Bidding a tile job: tile installers can count boxes, grout and thinset for the takeoff. Then move to the second tab and price labor, removal and margin from the same square footage.
How this tile calculator works
Enter the room in feet or the tile in centimeters, whichever is on your tape, and pick a common tile size or type your own. The tool finds the area, takes off any cut outs, divides by the space one tile fills including its grout joint, adds the overage for the pattern you chose and rounds up to whole tiles and whole boxes. It also reads grout bags off a manufacturer coverage chart for your tile size and joint, counts 50 lb bags of thinset for the trowel notch, and works out bullnose or trim pieces as edge length divided by piece length. Ordering short means a second batch that may not match in shade, which is why the boxes always round up.
How many tiles per 100 square feet, by tile size?
Divide 144 by the tile's length × width in inches to get tiles per square foot. With 1/8 in joints, 100 sq ft of 12 × 12 tile takes 98 tiles, or 108 once 10% is added.
| Tile size | One tile covers | Tiles per 100 sq ft | With 10% extra | With 15% extra |
|---|---|---|---|---|
| 3 × 6 in subway | 0.125 sq ft | 753 | 828 | 866 |
| 4 × 4 in | 0.111 sq ft | 847 | 931 | 974 |
| 6 × 6 in | 0.25 sq ft | 384 | 423 | 442 |
| 12 × 12 in | 1 sq ft | 98 | 108 | 113 |
| 6 × 24 in plank | 1 sq ft | 98 | 108 | 113 |
| 12 × 24 in | 2 sq ft | 50 | 55 | 57 |
| 18 × 18 in | 2.25 sq ft | 44 | 49 | 51 |
| 24 × 24 in | 4 sq ft | 25 | 28 | 29 |
| 24 × 48 in | 8 sq ft | 13 | 14 | 15 |
Counts allow for 1/8 in joints and round up to whole tiles. Mosaics come on sheets, so count sheets instead.
How much extra tile should you buy for each layout?
About 10% covers a straight layout. Go to 15% for diagonal or herringbone tile, or a room full of jogs and corners.
| Layout | Extra to order | Why it needs more |
|---|---|---|
| Straight grid, simple room | 5 to 10% | Only the edge rows get cut. 10% is the safe default for most floors. |
| Running bond or offset | About 10% | Every other row starts with a part tile at each wall. |
| Diagonal | 15% | Turning the tile 45 degrees leaves a triangle cut at every wall. |
| Herringbone | 10 to 20% | Each tile meets the wall at an angle. The calculator starts at 15%. |
| Lots of jogs and corners | 15% | Closets, islands and doorways multiply the cuts. |
| Small tile, borders or strong shade variation | 15 to 30% | Narrow planks, inset borders and color matching leave more pieces unused. |
Keep a few leftover tiles from the same lot after the job. If a tile cracks years later, the line may be discontinued.
How much grout and thinset do you need?
Bigger tiles and thinner joints use far less grout. A 25 lb bag of sanded grout covers about 345 sq ft of 12 × 12 tile with 1/8 in joints, but only 118 sq ft at 3/8 in.
| Tile size | 1/8 in joint | 3/16 in joint | 1/4 in joint | 3/8 in joint |
|---|---|---|---|---|
| 2 × 2 in mosaic | 88 sq ft | 73 sq ft | 50 sq ft | 40 sq ft |
| 4¼ × 4¼ in | 210 sq ft | 143 sq ft | 110 sq ft | 75 sq ft |
| 6 × 6 in | 263 sq ft | 178 sq ft | 136 sq ft | 93 sq ft |
| 12 × 12 in | 345 sq ft | 230 sq ft | 175 sq ft | 118 sq ft |
| 16 × 16 in | 458 sq ft | 305 sq ft | 225 sq ft | 144 sq ft |
| 24 × 24 in | 685 sq ft | 458 sq ft | 325 sq ft | 225 sq ft |
Square feet covered by one 25 lb bag of sanded grout. Sanded grout suits joints from 1/8 to 1/2 in; for joints up to 1/8 in, unsanded grout comes in 10 lb boxes.
How much does tile installation cost per square foot?
Porcelain or floor rated ceramic usually runs $9 to $25 per sq ft installed. Most installers charge about $5 to $9 per sq ft for labor, and the tile itself can cost anywhere from $1 to $35.
| Item | Typical price | What to know |
|---|---|---|
| Ceramic tile | $1 to $8 per sq ft | The cheapest option for floors, walls and backsplashes |
| Porcelain tile | $4 to $14 per sq ft | Denser and harder wearing than ceramic |
| Wood look porcelain | $5 to $15 per sq ft | Plank sizes, usually laid in an offset pattern |
| Natural stone, slate or marble | $7 to $25 per sq ft | Needs sealing, which adds labor |
| Glass accent tile | $12 to $35 per sq ft | Often sold as mosaic sheets, which take more grout and cutting time |
| Installation labor | $5 to $9 per sq ft | Can reach $22 for intricate patterns, mosaics or large format tile |
| Outdoor or patio tile | 15 to 20% more | Weather rated thinset and membranes |
| Removing old tile | $3 to $7 per sq ft | Demolition and haul away before the new tile goes in |
| Floor leveling | $2 to $5 per sq ft | When the floor is out more than 1/8 in over 10 ft |
Material prices are per square foot of tile, before tax. Add the overage from your layout to the square footage before you multiply.
How do tile installers estimate a job?
Takeoff first, then labor. A count that misses a closet or a niche shows up later as a second supply run nobody is paying for.
- Measure every surfaceFloors by length × width, walls by width × height, and each shower wall, niche and curb on its own line.
- Subtract the openingsTake out doors, windows and the tub footprint.
- Set the overage for the layout10% for a straight lay and 15% for diagonal or herringbone. A tiny bathroom with a toilet, a vanity and three doorways may need more, because almost every tile touching an edge gets cut.
- Count boxes, grout, thinset and trimRound tile up to whole boxes, then read grout off the coverage chart for the tile and joint.
- Price labor and prepLabor by the square foot, plus removal, leveling and waterproofing where the job needs them.
- Set the margin and send itBreak the quote into tile, setting materials, labor and prep. A homeowner holding two shower bids finds the itemized one easier to trust.
The Price the install tab follows these steps, starting from the square footage and box count on the first tab.
Tile installers: the next remodel lead rings while you are back buttering a 24 inch tile.
Set tile does not wait. Thinset skins over in minutes, so the phone goes unanswered on install days, and a homeowner comparing bathroom quotes simply dials the next installer on the list. ServiceAgent answers every call, asks about the room, the tile and the timeline, books the measure visit on your calendar and sends the follow up for you.
Book a free demoFrequently asked questions
Short answers on tile counts, overage, grout, units and what a tile job costs.
Book a free demoHow many tiles do I need for 100 square feet?
With 12 × 12 in tile and 1/8 in grout joints, 100 square feet takes 98 tiles, or 108 once you add 10 percent for cuts. Smaller tile climbs fast: 3 × 6 in subway tile needs 753 tiles for the same 100 square feet, and 828 with 10 percent extra.
How accurate is this tile calculator?
The math is exact for the measurements you enter. What changes the final count is the room itself: walls that are not square, extra cuts around a vanity or a floor vent, and how carefully offcuts get reused. The waste allowance covers that, and measuring each surface on site before you order keeps the count tight.
Do I need to round up the number of tiles?
Yes. Tiles are sold whole and usually by the box, so the calculator rounds up twice: first to whole tiles after the overage, then to whole boxes.
Can I use this calculator for walls and floors?
Yes. For a wall or backsplash, choose Wall under Surface, enter width and height, and subtract windows, doors or the tub as cut outs. Treat each wall as its own surface, or enter how many walls share the same size.
How do I convert tile sizes between inches and centimeters?
One inch is 2.54 centimeters, so a 12 inch tile is about 30 cm and a 24 inch tile about 60 cm. One square meter is 10.76 square feet. Switch the calculator to meters and cm and it converts everything for you, including the grout and thinset counts.
Do grout lines change how many tiles I need?
A little, and more with small tile. Each tile fills its own face plus one joint, so 1/8 in joints cut the count for 100 square feet of 12 × 12 tile from 100 to 98. With 3 × 6 subway tile the same joint drops it from 800 to 753, which is why the joint width is an input.
Should I buy extra tiles for future repairs?
Yes. Keep a few leftover tiles, ideally a full box, from the same production lot. Colors shift between lots and lines get discontinued, so a matching tile can be impossible to find when one cracks years later.
Does the estimate include grout, thinset and labor?
Yes. The first tab counts grout bags from a manufacturer coverage chart and 50 lb thinset bags for your trowel notch. The Price the install tab adds tile, setting materials, labor at about $5 to $9 per square foot, old tile removal and leveling.
How much extra tile do I need for herringbone or diagonal layouts?
Plan on 15 percent for a diagonal layout and 15 percent as a starting point for herringbone, where the usual range runs from 10 to 20 percent. A straight grid in a simple room needs about 10 percent.
How much does it cost to tile 100 square feet?
At the usual $9 to $25 per square foot installed for porcelain or floor rated ceramic, 100 square feet comes to roughly $900 to $2,500. Removing old tile adds $3 to $7 per square foot, and natural stone or glass tile pushes the material cost higher.
Is this tile calculator useful for tile installers?
Yes. Installers use the first tab for the takeoff and the second to price labor, removal, leveling and margin from the same square footage, then print or share the result. ServiceAgent answers the calls those quotes come from and books the measure visits.
Leads growth and product marketing for ServiceAgent at SaaS Labs, where he has worked in product marketing since 2020. Writes ServiceAgent's coverage of AI call answering, CRM and home services operations.
Published by ServiceAgent, the AI front office for home service teams. Estimates only. Actual tile counts and prices depend on the room, the layout, the carton size and your supplier. Measure each surface on site and check the tile, grout and thinset labels before you order.