How this calculator works
Thinset coverage depends mostly on your trowel size — bigger notches lay a thicker bed and cover less area. The calculator divides your tile area by the coverage for the chosen trowel (per 50 lb bag).
100 ÷ 70 = 1.43 → 2 bags of thinset.
Order enough thinset without overmixing
Measure floors, walls, niches, and shower benches separately, then add their areas together. Round up to a whole bag after dividing the total by the selected coverage. Use the coverage printed on your exact thinset bag as the purchase check: trowel notch, tile back profile, substrate flatness, and mixing can change actual yield. A 10% planning cushion can help on uneven substrates or when back-buttering large-format tile. Match the trowel to your tile size — the manufacturer lists the recommended notch — and mix only what you can spread and tile within the product’s pot life. Before ordering, confirm tile quantity with the tile calculator and plan joints with the grout calculator.
Frequently asked questions
How much thinset for 100 square feet?
Roughly 1–2 bags (50 lb) depending on trowel size.
How much area does a bag of thinset cover?
About 45–95 sq ft per 50 lb bag, depending on the trowel notch and substrate.
How many bags of thinset do I need for 100 square feet?
Usually 2 bags with a 1/4-inch square-notch trowel, but check the product coverage and add extra for uneven surfaces.
How much thinset do I need for a shower?
Calculate the floor and each wall separately, add the areas together, and use the manufacturer coverage for the trowel recommended for your tile.