Thinset Calculator
A 10 by 16 foot floor at 80 square feet per 50 lb bag is 2 bags. 80 is the low end of an 80–95 planning range for a 1/4 by 1/4 inch notch.
Last updated . Length and width start in feet. Switch them to inches, yards, or meters. Waste starts at 0. Coverage starts at 80 ft² per 50 lb bag, the low end of a planning range. These ranges are not a brand chart. No price.
Pick a trowel notch, then type the square feet per 50 lb bag from the bag if you have it. Bags are the floor area after waste, divided by that coverage, rounded up.
Grout in the joints: grout calculator. Tile count: tile calculator. A wall mortar percent: mortar calculator.
Thinset bags
Each notch fills the coverage with the low end of a planning range for a 50 lb bag. 1/4 × 1/4 in is 80–95, 1/4 × 3/8 in is 60–75, and 1/2 × 1/2 in is 35–50. Type the square feet on the bag. These are not a brand’s coverage. No price.
Results
How the bags are counted
Bags = floor area after waste ÷ square feet per 50 lb bag, rounded up. The notch menu writes the low end of a planning range into the coverage field, so the first count orders more bags. 1/4 × 1/4 in is 80–95, 1/4 × 3/8 in is 60–75, and 1/2 × 1/2 in is 35–50. Those ranges belong to this page. They are not a manufacturer chart. Type the square feet on the bag you are buying.
The opening floor is 10 by 16 feet, 160.00 ft² and 14.86 m². At 80 ft² per 50 lb bag and no waste, 160 ÷ 80 = 2.00, so the order is 2 bags. Waste starts at 0. Ten percent turns 160.00 into 176.00 and the order into 3 bags.
Worked example
Leave every field as it opens: floor 10 ft by 16 ft, notch 1/4 × 1/4 in, coverage 80, waste 0. Area reads 160.00 ft² · 14.86 m². Coverage reads 80.00 ft² per 50 lb. With waste reads 160.00 ft². Bags read 2.
The same 160.00 square foot floor at both ends of each planning range, and at 10 percent waste.
| Notch | Coverage | Waste | With waste | Bags |
|---|---|---|---|---|
| 1/4 × 1/4 in | 80 ft² | 0% | 160.00 ft² | 2 |
| 1/4 × 1/4 in | 95 ft² | 0% | 160.00 ft² | 2 |
| 1/4 × 3/8 in | 60 ft² | 0% | 160.00 ft² | 3 |
| 1/4 × 3/8 in | 75 ft² | 0% | 160.00 ft² | 3 |
| 1/2 × 1/2 in | 35 ft² | 0% | 160.00 ft² | 5 |
| 1/2 × 1/2 in | 50 ft² | 0% | 160.00 ft² | 4 |
| 1/4 × 1/4 in | 80 ft² | 10% | 176.00 ft² | 3 |
Frequently asked questions
How many bags of thinset for a 10 by 16 floor?
Leave the floor at 10 ft by 16 ft, the notch at 1/4 × 1/4 in, and the coverage at 80. Area reads 160.00 ft² · 14.86 m². Coverage reads 80.00 ft² per 50 lb. With waste reads 160.00 ft². Bags read 2, because 160 ÷ 80 = 2.00.
What do the notch ranges mean?
Each notch fills the coverage with the low end of a planning range for a 50 lb bag. 1/4 × 1/4 in is 80–95, 1/4 × 3/8 in is 60–75, and 1/2 × 1/2 in is 35–50. These are this page’s planning figures, not a brand chart. Type the square feet printed on the bag.
What if the bag says 95 square feet?
Type 95 in the coverage field and leave the 10 by 16 floor. Coverage reads 95.00 ft² per 50 lb. 160 ÷ 95 is 1.68, and bags still read 2. The notch stays a label. The coverage field is what the bag count uses.
How many bags for a 1/2 by 1/2 notch?
Choose 1/2 × 1/2 in. Coverage becomes 35, the low end of 35–50. Bags read 5. Type 50, the high end of that range, and 160 ÷ 50 = 3.20, so bags read 4. The low end orders more bags.
What does 10 percent waste change?
Set the notch back to 1/4 × 1/4 in so coverage is 80, then set waste to 10. With waste reads 176.00 ft². Bags read 3. Waste starts at 0. It is an allowance you add, not a coverage from the bag.
How many bags for a 1/4 by 3/8 notch?
Choose 1/4 × 3/8 in. Coverage becomes 60. On the 160.00 ft² floor, 160 ÷ 60 is 2.67, and bags read 3. Type 75, the high end of 60–75, and bags still read 3, because 160 ÷ 75 is 2.13.
Is this grout, mortar, or screed?
No. This page is bags of thinset under the tile, from square feet per 50 lb bag. Grout in the joints is the grout calculator. A percent of a brick or block wall is the mortar calculator. A sand-and-cement screed, mixed from cement and sand, is the screed calculator.