Tile Calculator

How to use the tile calculator

1. Measure the floor or wall: length and width for a floor, length and height for a wall or backsplash. Measure each part separately and add them up if the area is not a rectangle.
2. Enter the tile’s size and pick the layout, the grout joint, the tile’s thickness and the trowel your thinset bag gives for that tile. Add the square feet printed on the box to get the boxes.
3. Read the tiles and boxes to buy, the grout (sanded or non-sanded, and how much) and the bags of thinset. Copy link keeps the result.

The rules the calculator uses

• Extra tile: buy at least 10% more than the area for cuts, breakage and repairs; 15% for tile with a fancy shape or pattern; laid diagonally, 20% more on top of that 10%. That is the guidance of MSI, a US tile supplier. Keep the leftovers: a later batch rarely matches in shade.
• Grout fills the joints, so the amount is the joints’ length × their width × the tile’s thickness. The weight per cubic inch comes from Custom Building Products’ own coverage charts for Polyblend grout, and the calculator matches those charts to within 7% for tiles 4″ and up. Non-sanded grout is for joints up to 1/8″ and sanded for 1/8″ to 1/2″ (the same data sheets).
• Thinset per 50 lb bag, from Custom’s VersaBond data sheets: 85–95 sq ft with a 1/4 × 1/4″ square notch, 60–67 with 1/4 × 3/8″, 42–47 with 1/2 × 1/2″. Larger tiles need deeper notches to be fully bedded.

Tiles and grout for 100 sq ft

With 10% extra, laid straight, and sanded grout:

Small tiles have far more joint per square foot, which is why a subway backsplash takes more grout than a large-tile floor twice its size.

Three worked examples

A 10′ × 8′ bathroom floor in 12″ × 24″ tile. 80 sq ft, so buy 88 sq ft: 44 tiles. At a 1/8″ joint it takes about 4.2 lb of sanded grout, one 7 lb bag, and 2 bags of thinset with a 1/4 × 3/8″ notch.

A 12′ subway-tile backsplash, 18″ high. 18 sq ft of 3″ × 6″ tile: buy 159 tiles. The 1/16″ joints take non-sanded grout, about 1.2 lb (one 10 lb box), and one bag of thinset with a 1/4 × 1/4″ notch.

A 14′ × 12′ kitchen in 12″ × 12″ tile, laid diagonally. 168 sq ft plus 32% for the angled cuts: 222 tiles, or 15 boxes of 15 sq ft. About 11.8 lb of sanded grout (one 25 lb bag) and 3 bags of thinset.

Common tile mistakes

• Buying exactly the area. Every row ends in a cut, and a few tiles crack. Without the extra you make a second trip, and the second batch may not match the first.
• Sanded grout in a 1/16″ joint. The sand cannot get into a joint that narrow. Use non-sanded up to 1/8″ and sanded from 1/8″.
• Too shallow a trowel for a large tile. A large tile on a 1/4″ notch may not be fully bedded, leaving hollow spots under it. The thinset maker names deeper notches for larger tiles; check the bag.
• Forgetting the edges. An outside corner or the top of a backsplash needs a trim or bullnose piece; count them with the tile, from the same batch.

Planning a whole bathroom? The bathroom layout planner checks the fixtures fit before you tile, and the bathroom remodel cost calculator prices the job. Try the finished room in the free 2D room planner.

Read next

• Checkerboard bathroom tile ideas
• How to pick a shower tile combination
• Tub tile ideas for a spa-like bathroom
• Zellige tile bathroom ideas