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

Tiling a 14 × 30 ft room with 12″ tile

12" tiles needed
462tiles
462 ft² of tile for a 14 × 30 ft room
Floor area420ft²
Buy for+10% cuts and breakage462ft²
12" × 12" tiles462tiles
Thinset (50 lb bags)70 ft² per bag with a 1/4" × 3/8" square-notch7bags
Grout (0.125" joints)2 × 25 lb bags30.9lb
Room width
14 ft
Room length
30 ft
Tile size
12 in

Tiles, and then some

The floor is 420 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 462 ft² — 10% over.

At 12″ square that works out to 462 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 12″ tile you want a 1/4" × 3/8" square-notch, which is why the bag count here is 7 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 12" tile needs a 1/4" × 3/8" square-notch, so a 50 lb bag covers about 70 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 0.375" tile thickness. Wider joints raise it quickly.

Nearby sizes