HowMuchIt / Tile
How much tile do I need?
Measure the floor or wall, divide by what one tile covers, then add extra for the cuts. The extra is the part people get wrong, and it depends on the layout more than on the room.
Work out your tile
| Tile | Sq ft per tile | Tiles for 100 sq ft, plus 10 percent |
|---|---|---|
| 6 x 6 in | 0.25 | 440 |
| 12 x 12 in | 1 | 110 |
| 12 x 24 in | 2 | 55 |
| 24 x 24 in | 4 | 28 |
Thin-set bags use the low end of each range (80 or 60 sq ft), so you do not run short mid-floor. Lightweight mortars cover more: the bag gives its own figure.
Measuring a floor that is not a rectangle
Few bathrooms are a clean rectangle once you count the closet, the tub and the bump around the toilet. Split the floor into rectangles you can measure with a tape, work out each one, and add them. Skip what will never get tile, like the space under a vanity that sits on the subfloor, but measure to the wall behind a toilet: the tile goes under it. Write the numbers down as you go; it is easy to measure the same strip twice.
Why the extra matters
Every row ends with a cut tile, and some cuts break or come out wrong. On a straight layout, ten percent covers that. Laid on a diagonal or in a herringbone, almost every tile along the walls is a cut, so plan fifteen to twenty percent. Buy it all at once: tile is made in batches, and the shade and even the size can shift a little from one batch to the next. A box bought later to finish the job may not match.
Questions people ask
How much extra tile should I buy?
At least ten percent on a straight layout, fifteen to twenty percent for diagonal or herringbone. The calculator adds it for you; change the layout to see the difference.
How many tiles do I need for a shower or a floor?
Area in square feet divided by one tile's area (length times width in inches, over 144), then the extra. For a shower, do each wall as its own rectangle and add the floor separately.
How much thin-set do I need?
With a 1/4 by 1/4 inch notched trowel, a 50 lb bag of standard thin-set covers roughly 80 to 95 square feet; with a 1/4 by 3/8 inch notch, about 60 to 70. Bigger tiles usually call for the bigger notch.
How do I work out grout?
Grout depends on the tile size and the joint width, so use the chart printed by your grout's maker. Bigger tiles and narrower joints need less. Joints are never narrower than 1/16 inch; up to 1/8 inch takes unsanded grout, wider takes sanded.
What do I do with the leftovers?
Keep a few. A cracked tile in five years is an easy fix when you have a spare from the same batch, and a hard one when the color has been discontinued.
Good to know
- Measure the area as length times width in feet; split an L-shaped or odd area into rectangles, find each area and add them.1,2
- One tile's area in square feet is its length times width in inches divided by 144 (a 6 x 6 in tile covers 0.25 sq ft).1,2
- Tiles (or boxes) needed = area to cover divided by the area one tile (or one box) covers, before adding extra.1,3
- Round up, never down: round the area up to the next whole square foot and the count up to the next whole box.1,2
- For a straight layout, buy at least 10 percent more tile than the measured area to cover cuts, breakage and mistakes.1,4,5
- Diagonal and herringbone layouts leave more cut pieces, so raise the extra to about 15 to 20 percent.1,4
- Buy all the tile, extras included, at one time: shade and size can differ from one production batch to the next.4,5,6
- Keep the leftover tiles after the job for future repairs; the color or style may be discontinued later.1,4,6
- With a 1/4 x 1/4 in square-notch trowel, a 50 lb bag of standard thin-set covers roughly 80 to 95 sq ft.7,8
- With a 1/4 x 3/8 in square-notch trowel, the same 50 lb bag covers only about 60 to 70 sq ft.7,8
- Unsanded grout is for joints up to 1/8 in; sanded grout is for joints from 1/8 in up to about 1/2 in or wider.9,10,11
- Grout joints are never narrower than 1/16 in, even with rectified tile.10,12
- A bag of grout covers more floor with bigger tiles and narrower joints, so grout must be estimated from tile size and joint width.9,11
How we checked this page
Checked on October 27, 2026. We kept a fact only when two independent publishers agree, and each one is numbered to its sources below. Where sources give different numbers, we keep only what they share. We never write a price. This page was written with an AI assistant and checked against the sources below.
Sources
- How Much Tile Do I Need?, Bob Vila
- Tile School: Doing the Math, Fireclay Tile
- How Much Ceramic Tile Do You Need?, Dummies (Wiley)
- How much extra tile to buy: planning for a flawless installation, Cle Tile
- How Much Extra Tile To Buy?, Arizona Tile
- Should I order any overage or extra material? How much?, Clay Imports
- MultiSet Economical Thin-Set Mortar, CUSTOM Building Products
- 253 Gold sell sheet (DS-1676), LATICRETE International
- Polyblend Plus Sanded and NonSanded Grout - Technical Data Sheet, CUSTOM Building Products
- Keracolor U - Premium Unsanded Grout with Polymer, MAPEI
- Keracolor S Product Data Sheet (copy on BuildSite), MAPEI
- Want credit card grout joints? Check tile industry standards, Ceramic Tile Foundation