Tile Calculator
This free tile calculator turns your floor or wall measurements, tile size and grout joint into the number of tiles and boxes to buy, with waste for straight, diagonal or herringbone layouts. It also works out bags of thinset for the right trowel and bags of grout, and gives you a cost.
Laying planks or carpet instead? Use the Flooring Calculator for boxes, underlayment and trim.
What this calculator does
It works out what a tile job needs: the tiles (and boxes, if you enter what's in a box), thinset mortar to set them and grout to fill the joints. You get a shopping list and a cost for doing it yourself versus hiring a tile setter. It works for floors, walls and backsplashes.
How it's calculated
- Area: each room's (or wall's) measurements multiplied, added up, minus areas left out. Area to buy is that × (1 + waste): 10% straight, 15% diagonal, 20% herringbone.
- Tiles: area to buy × 144 ÷ ((W + j) × (L + j)), where W and L are the tile size in inches and j is the grout joint, rounded up.
- Boxes: tiles ÷ pieces per box, or area to buy ÷ sq ft per box, rounded up.
- Thinset: area ÷ the coverage of a 50 lb bag for your trowel notch: 100 sq ft for a 3/16 in V-notch, 90 for 1/4 × 1/4 in, 60 for 1/4 × 3/8 in, 42 for 1/2 × 1/2 in.
- Grout: area × 144 × (W + L) ÷ (W × L) × j × tile thickness × 0.06 lb per cubic inch, plus 10%, in 10 or 25 lb bags.
- Cost: each line's quantity × its unit price, added up. Installed cost adds a typical tile-setting labor rate per sq ft.
Worked example
A 10 × 10 ft kitchen floor in 12 × 12 in porcelain, 3/8 in thick, with 1/8 in joints, laid straight. The floor is 100 sq ft; with 10% waste that's 110 sq ft, or 15,840 sq in. Each tile with its joint covers 12.125 × 12.125 = 147.02 sq in, so 15,840 ÷ 147.02 = 107.7, rounded up to 108 tiles. A 12 in tile calls for a 1/4 × 3/8 in trowel: 100 ÷ 60 = 1.7, so 2 bags of thinset. Grout: 100 × 144 × 24/144 × 0.125 × 0.375 × 0.06 = 6.75 lb, plus 10% is 7.4 lb, so one 10 lb bag. Expect about $272–$870 in materials, or $772–$2,070 installed.
Frequently asked questions
How many tiles do I need for 100 sq ft?
With 12 x 12 in tile and 1/8 in grout joints, 100 sq ft needs 108 tiles, including 10% waste for a straight layout. Each tile plus its joint covers 12.125 x 12.125 in, which is why the count is lower than the 110 you get by ignoring the joint. With 12 x 24 in tile it is 55 tiles.
How much waste should I add for diagonal tile?
Plan on about 15% extra for a diagonal layout, compared with 10% for a straight one, because every tile along the walls is cut at an angle. Herringbone and chevron need about 20%. A 100 sq ft floor of 12 x 12 in tile needs 113 tiles laid diagonally instead of 108 laid straight.
How much thinset do I need per square foot?
A 50 lb bag covers about 90 to 100 sq ft with a 1/4 x 1/4 in square-notch trowel, 60 to 67 sq ft with 1/4 x 3/8 in, and 42 to 47 sq ft with 1/2 x 1/2 in, per Custom Building Products' published chart. This calculator uses the low end of each range. Choose the notch by tile size: 1/4 x 1/4 in under 8 in, 1/4 x 3/8 in from 8 to 15 in, and 1/2 x 1/2 in above that.
How much grout do I need?
Grout fills the joints, so it depends on tile size, joint width and tile thickness. 100 sq ft of 12 x 12 x 3/8 in tile with 1/8 in joints takes about 6.75 lb of grout, or 7.4 lb with 10% extra for mixing and cleanup: one 10 lb bag. Smaller tile needs far more; 4 x 4 in tile of the same thickness takes about three times as much.
Should I use sanded or unsanded grout?
Use unsanded grout for joints up to 1/8 in and sanded grout for joints of 1/8 in and wider. At exactly 1/8 in either works, and sanded is the usual choice for floors. Unsanded grout in a wide joint can shrink and crack, and sanded grout is hard to pack into a 1/16 in joint.
Limitations
This is an estimate for rectangular areas, not a tile layout. Thinset coverage is the low end of a manufacturer's chart and real use varies with the substrate and how flat the tile is; large tiles that need back-buttering use more. The grout figure runs high for mosaic sheets. Backer board, waterproofing membrane, uncoupling mat, spacers, leveling clips, edge trim and grout sealer aren't included. Check the tile maker's instructions for the trowel and grout they require. If the floor needs a new slab first, see the Concrete Slab Calculator; for new walls behind a backsplash or shower, see the Drywall Calculator.
Put this calculator on your site
Run a blog or business site for DIYers, homeowners or contractors? You can embed the Tile Calculator as a free widget — responsive, no registration, and no ads or tracking added to your page.
Cite this calculator
Using this tool in a class, a paper or an article? Copy a ready-made reference: