What this calculator does
This tool estimates how many bags of thinset mortar you need for a tile installation, based on the area to be tiled and the coverage rate for your chosen trowel notch size.
The formula
Bags needed = (area × (1 + waste percentage)) ÷ coverage per bag. Larger trowel notches apply thicker mortar beds (needed for bigger or heavier tiles) and cover less area per standard 50 lb bag.
Coverage rates are approximate and vary by mortar brand, substrate flatness, and installer technique — always check your specific product’s technical data sheet.
Last reviewed August 2026