TileQuantCoverage math for tile, thinset and grout — before you buy.

Tiling a 24 × 28 ft room with 18″ tile

18" tiles needed
329tiles
739.2 ft² of tile for a 24 × 28 ft room
Floor area672ft²
Buy for+10% cuts and breakage739.2ft²
18" × 18" tiles329tiles
Thinset (50 lb bags)45 ft² per bag with a 1/2" × 1/2" square-notch17bags
Grout (0.125" joints)2 × 25 lb bags44.3lb
Room width
24 ft
Room length
28 ft
Tile size
18 in

Tiles, and then some

The floor is 672 ft². Buying exactly that much is how people end up back at the store: cuts at the walls, the odd broken tile and a spare box for future repairs mean you order 739.2 ft² — 10% over.

At 18″ square that works out to 329 tiles.

Thinset depends on the tile, not the room

This is where rule-of-thumb estimates go wrong. A bigger tile needs a bigger notched trowel, and a bigger notch puts down more mortar per square foot. For 18″ tile you want a 1/2" × 1/2" square-notch, which is why the bag count here is 17 rather than whatever a generic calculator returns.

Before you order

Measure the room at more than one point. Rooms are rarely square, and the widest measurement is the one that decides how many tiles the last row needs.

Notes

  • Thinset coverage is set by trowel size, not by room size — a 18" tile needs a 1/2" × 1/2" square-notch, so a 50 lb bag covers about 45 ft².
  • Add 15% instead of 10% for a diagonal layout, a room with many jogs, or if the tile has a pattern that has to line up.
  • Grout is figured at 0.125" joints and 0.5" tile thickness. Wider joints raise it quickly.

Nearby sizes