Thinset Calculator
Enter the area and pick the trowel notch, and get the bags of thinset from the maker's printed coverage range, counted on the lowest figure and rounded up once, with the count at the highest figure beside it.
Estimates for planning, not professional advice. Read the full notice.
Example: a tiled floor
2 50 lb bags
- Bags at the lowest coverage figure 1.33 bags
- Bags at the highest coverage figure 2 × 50 lb bags
Estimate for planning, from what you entered and the product data shown. Check product labels and your supplier before you buy.
Your project
Enter a size to see your total.
Each product is rounded up once for the whole project, so the total can be less than the items bought alone added together. A line counted from a cut layout (sheets, boards or tiles laid out piece by piece) is counted for each item and added.
Shopping list
| Item | Size | Buy |
|---|---|---|
| Thinset mortar, by the bag | 50 lb bag | 2 |
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Worked example: a tiled floor
Show the working
- Divide the area by the lowest coverage per bag 80 ft² ÷ 60 sq ft = 1.33 bags
- Round up once, to whole bags 1.33 bags = 2 × 50 lb bags
Assumptions
The figures behind the example. Sourced figures link to their source below; a default is a starting value to check against your label or supplier.
| Assumption | Value | Details and changes |
|---|---|---|
| Lowest coverage per bag at the starting notch | 60 ft²[1] | |
| Square feet one 50 lb bag covers by square-notch trowel, as a lowest and a highest figure, per the maker's coverage chart. | ||
| Highest coverage per bag at the starting notch | 67 ft²[1] | |
| Square feet one 50 lb bag covers by square-notch trowel, as a lowest and a highest figure, per the maker's coverage chart. | ||
| Bag size the chart is printed for | 50 lb[1] | |
| Square feet one 50 lb bag covers by square-notch trowel, as a lowest and a highest figure, per the maker's coverage chart. | ||
| Mortar contact the maker requires in dry areas | 80%[1] | |
| The thinset maker's required mortar coverage between substrate and tile underside, for dry areas and for wet areas. | ||
| Mortar contact the maker requires in wet areas | 95%[1] | |
| The thinset maker's required mortar coverage between substrate and tile underside, for dry areas and for wet areas. | ||
Feet and inches, like 12' 6"
Thinset coverage and bags by trowel notch
The maker's lowest and highest square feet per bag for each trowel notch, and the bags for the example area at each
| Trowel notch (inches) | Lowest coverage per bag | Highest coverage per bag | Bags for the example area at the lowest | Bags for the example area at the highest |
|---|---|---|---|---|
| 1/4x1/4x1/4 | 90 ft² | 100 ft² | 1 | 1 |
| 1/4x3/8x1/4 | 60 ft² | 67 ft² | 2 | 2 |
| 1/2x1/2x1/2 | 42 ft² | 47 ft² | 2 | 2 |
| 3/4x9/16x3/8 U-notch at 45 | 34 ft² | 38 ft² | 3 | 3 |
| 3/4x9/16x3/8 U-notch at 30 | 42 ft² | 47 ft² | 2 | 2 |
Figures in the Lowest coverage per bag and Highest coverage per bag columns are per Custom Building Products' product page, checked Nov 12, 2026.
Product names are trademarks of their owners. HoneyDoMath is not affiliated with, sponsored by or endorsed by these makers. Figures come from each maker's published sheets and are shown for information only.
Source: [1]
The chart gives a range because coverage depends on how the mortar is spread; the calculator counts on the lowest figure so the count is not short against the chart.
Questions
How much thinset do I need for large tile?
It depends on the trowel notch the tile calls for. The table gives the maker's printed coverage per bag for each notch, so pick the notch and the calculator counts the bags for your area. Larger tile often calls for a larger notch.
What is mortar contact?
It is how much of the tile's underside is covered by mortar. The maker's sheet gives a required contact for dry areas and for wet areas, shown in the assumptions; the calculator does not measure contact, it only counts bags from the coverage chart.
Sources (1)
-
VersaBond Professional Thin-Set Mortar, coverage chart (opens in new tab), Custom Building Products, Product page, coverage chart.
Manufacturer data.
“SQUARE FOOT COVERAGE PER 50 LB BAG … 1/4″ x 1/4″ x 1/4″ … Square-Notch … 90 ft² … 100 ft² … 1/4″ x 3/8″ x 1/4″ … Square-Notch … 60 ft² … 67 ft² … 1/2″ x 1/2″ x 1/2″ … Square-Notch … 42 ft² … 47 ft²”
“Mortar coverage between the substrate and tile underside is required to be ≥80% for dry areas and ≥95% for wet areas and exteriors”
“SQUARE FOOT COVERAGE PER 50 LB BAG … 3/4″ × 9/16″ × 3/8″ … U- Notch @45 angle … 34 ft² … 38 ft² … 3/4″ × 9/16″ × 3/8″ … U- Notch @30 angle … 42 ft² … 47 ft²”
“Chart for estimating purposes. Coverage may vary based on installation practices and jobsite conditions.”
Per Custom Building Products' product page, checked Nov 12, 2026. Figures and codes change; verify with the source. Back to where this is used (Source 1)
These are summaries of what the sources say, not professional advice. Codes and product data change. Check with your building department and the product label about your own project.
Sources
- [1] Custom Building Products, VersaBond Professional Thin-Set Mortar, coverage chart. Checked November 12, 2026. https://www.custombuildingproducts.com/products/versabond-professional-thin-set-mortar