Thinset Calculator: How Many Bags of Mortar Do You Need?

Your details

Length of the room or surface being tiled.
ft
Width of the room or surface being tiled.
ft
Longest side of one tile. Larger tiles need a deeper trowel notch.
Notch depth determines how much mortar is applied. Choose "Auto" to let the calculator pick the right notch for your tile size.
Tiles 15" or larger should also have thinset spread on the tile back (back-buttering) to reach the TCNA-required 95% coverage. Adds roughly 50% more thinset.
Add 10% for straight layouts, 15% for diagonals, up to 20% for complex patterns.
%
Common sizes: 50 lb and 25 lb bags (US); 20 kg bags (Europe).
lb
Leave at 0 to skip the cost estimate.
USD
Thinset needed
198

Total weight including wastage

Project area120
Bags to buy4
Trowel notch used3/8" x 3/8" square-notch
Coverage per bag33
Project area (sq ft)120
Thinset weight (lb/kg)198
Coverage per bag33

You need 4 bags for this project.

  • You need 4 50-lb bags of thinset (198.0 lb total with 10% wastage).
  • Trowel notch used: 3/8" x 3/8" square-notch (9.5 mm / 0.375" depth).
  • Buy one extra bag as a buffer: running out mid-project can cause grout-line colour differences if you open a new lot.

Next stepAllow the thinset to cure for at least 24 hours before grouting. In wet areas, use a polymer-modified thinset rated for that application.

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