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).
Worked example — 100 sq ft with a 1/4 in square-notch trowel (~70 sq ft/bag):
100 ÷ 70 = 1.43 → 2 bags of thinset.
100 ÷ 70 = 1.43 → 2 bags of thinset.
Bigger tiles need bigger notches
Large-format tiles and uneven substrates need a deeper notch (1/2 in), which uses more thinset. Match the trowel to your tile size — the manufacturer lists the recommended notch.
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.