Thinset Mortar Coverage Calculator

About this calculator

Thinset mortar is the cement-based adhesive troweled down to bond tile to a floor or wall, and each bag's coverage varies with the trowel notch size and tile format — a bag might cover anywhere from 40 to over 100 square feet depending on those factors and the manufacturer's spec. This calculator divides your total tile area by the coverage rate printed on the bag, then adds a waste allowance for spillage, uneven substrates, and trowel technique to get the number of bags to buy.

Tile installers and DIY renovators use a coverage calculation like this before a job to avoid two common problems: running short mid-installation when mortar has already started to set (forcing a rushed extra trip to the store), or over-ordering and paying for bags that go unused. It's a standard step alongside tile-quantity and grout calculations when budgeting a tiling project.