About this calculator
Bags of thinset mortar by area and trowel size.
How it’s calculated
Coverage per 50 lb bag: about 90 sq ft with a ¼" square notch, 70 sq ft with ¼" × ⅜", and 45 sq ft with ½" square.
Worked example
With these inputs:
- Measure by
- Length × width
- Length
- 15 ft
- Width
- 12 ft
- Trowel notch
- ¼" × ¼" square
- Back-butter tiles (+30%)
- No
- Waste allowance
- 10%
the result is:
- Thinset bags (50 lb)
- 3 bags
Tips from the trade
- Choose the notch for the tile size: bigger tiles need bigger notches.
- Lift a tile now and then to check for full coverage.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and local building codes before ordering.