For every sized tiling project, this thinset calculator can help you respond to the question, “How much thinset do I need?” Have you ever had contact with it before with some project in your house? Is it the same as adhesives or grout?

With this calculator, you will learn what a thinset is and what trowel size and thinset thickness to use for different tile sizes. You will also learn the formula for calculating thinset, how many thinset bags you need per square foot, and so much more. You have our support do not worry.

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What is thinset?

Thinset (thinset mortar, thinset grout, dry-set mortar, or dry bond mortar) is a water-retaining adhesive (adhesives) mortar comprised of grout, fine sand, and an alkyl derivative of cellulose. We typically use it to secure or support tile or stone to grout or concrete surfaces. Mosaicists love it since it is great tool for outdoor projects, and installation is very easy. There are two varieties of thinset available: modified and unmodified (polymer-modified).

Modified vs unmodified thinset

Thinset has been around for quite a long time. Professionals from the past know how to use it and install it effectively. However, in recent decades, the modified thinset has gained popularity. Its simplicity attracts an increasing number of installations.

Modified thinset systems incorporate different retention products, such as latex polymers, that can improve their performance and strength, as opposed to unmodified mortar, which comprises only a blend of Portland grout, sand, and water retention agents. Furthermore, some modified thinset does not require mixing with water before installation on the floor. This means less effort for you and more durable concrete for the consumer.

Thinset vs Mortar, Thinset vs. Mastic

Thinset is divided into two types: unmodified thinset and modified thinset. The presence of polymers, mainly latex, in the modified thinset is the fundamental distinction between the two.

Because modified thinset contains latex, it must be allowed to cure thoroughly before it can be used to lay tiles on concrete or plywood. However, soaking some of the water in the thinset mix, concrete and plywood may help modified thinset dry faster.

On the other hand, unmodified thinset cures faster with the help of moisture than concrete. As a result, tile installers prefer to apply unmodified thinset to waterproof surfaces with membrane-type waterproofing products. Such materials do not absorb water, although the thinset requires a little longer to cure as a result. Nonetheless, you may always look at the thinset packing to see which thinset is ideal for your privacy product or products.

It is very important to say a product like grout should not be used instead of thinset. The reason is that products like the mentioned grout do not stick to the floor tiles like thinset.

Trowel Size and Thinset Thickness – Table

The notch size determines the size of the beads produced by the trowel. When the tiles are installed, these beads are crushed flat, reducing the possibility of air pockets between both the tiles and the base. In the table below, you can find out what trowel size and thinset thickness to use for different tile sizes:

For tile sizeTrowel notch shapeThinset thickness
2″ x 2″ (5×5 cm) and smaller\frac {3}{16˝} \cdot \frac {5}{32˝} (5×5 mm) V-notch \frac {1} {9"}– 2.0 mm
4″ x 4″ (10×10 cm) and smaller\frac {1}{4˝} \cdot \frac {3}{16˝} (6×5 mm) V-notch \frac {1} {9"}– 2.4 mm
8″ x 8″ (20×20 cm) and smaller\frac {1}{4˝} \cdot \frac {1}{4˝} (6×6 mm) square-notch \frac {1} {8"}– 3.5 mm
8″ x 8″ (20×20 cm) and smaller\frac {1}{4˝} \cdot \frac {5}{16˝} (6×8 mm) U-notch \frac {1} {7"}– 4.0 mm
12″ x 12″ (30×30 cm) and smaller\frac {1}{4˝} \cdot \frac {3}{8˝} (6×9.5 mm) square-notch \frac {1} {5"} – 5.0 mm
12″ x 12″ (30×30 cm) and smaller\frac {1}{4˝} \cdot \frac {3}{8˝} (6×9.5 mm) U-notch \frac {1} {5"} – 5.0 mm
12″ x 12″ (30×30 cm) and larger\frac {1}{2˝} \cdot \frac {1}{2˝} (13×13 mm) square-notch \frac {1} {4"} – 7.0 mm
12″ x 12″ (30×30 cm) and larger\frac {1}{4˝} \cdot \frac {1}{2˝} (6×12 mm) U-notch \frac {1} {4"}– 7.0 mm
12″ x 12″ (30×30 cm) and larger\frac {3}{4˝} \cdot \frac {5}{8˝} (19×16 mm) U-notch \frac {1} {3"} – 8.0 mm

Thinset Formula

To calculate the amount of thinset required by volume, multiply the total area of the substrate on which our tiles will be installed by the thinset thickness required to hold the tiles in place, as given in the equation below:

Volume of thinset = area of substrate * thinset thickness

Thinset Calculator – How Much Thinset Do I Need?

The amount of thinset you will need is determined by the size of the tile you want to place and the area of your product design, doesn’t matter is it wall or floor. Larger tiles require a thicker thinset to support them, but smaller tiles can be secured with installation of a thinner thinset. We can use a notched trowel to establish a constant thickness throughout an area by leaving a uniform set of thinset beads throughout the base.

Thinset Calculator – Example

To calculate how much thinset you need, you must follow four simple steps:

  • Enter the area you are working on; its length and breadth. If you already know how much space you will need, you can type it into the Total area to be tiled field.
  • Select the tile size you want to use. This will produce the maximum thinset thickness appropriate for your tile, ensuring adequate adhesion to your tiles. If you want to, you can also specify your preferred thinset thickness.
  • Our thinset calculator will calculate the volume of thinset and the quantity of dry thinset bags required for your project. As you can see, the values for wastage and weight per bag have been predetermined.
  • Going to the advanced mode of our thinset calculator will allow you to modify the density of the thinset. You can also change the percentage of dry material in your thinset mix there. This is set to 50% by default, implying that the water and dried thinset are mixed in a 1:1 ratio.


How do I calculate how much thinset I need?

First, calculate the amount of thinset you’ll need by multiplying the square footage of your room or wall by the size of your tile and the size of your trowel. For example, three bags of tools (thinset) are required for coverage a 120 square foot room with 16-inch tiles.

How many bags of thinset do I need per square foot?

Divide 95 percent of the total square footage of your product. The number should be rounded up to the nearest whole number. Multiply the quantity by two if you’re using large tiles and a 1/2-inch notched trowel. The result is how much you need to coverage a square foot.

How thick should my thinset be?

A thinset coating of 3/16 to 1/8-inch thickness is sufficient in most cases.

What happens if you put too much water in thinset?

The mixture grows thinner as you add additional water. As a result, there are fewer mortar molecules per water molecule. When the water has evaporated, the construction is left with more air or holes, which weakens the overall structure, making it less resistant to weight and time, reducing the tile job’s lifespan.

How long does it take for thinset to dry?

Thinset mortar, also known as dry-set mortar or dry bond mortar, has a water-retaining ingredient that aids in the curing and hydration. The most popular applications are tiles and counter-tops. The cure time for thinset mortar is between 24 and 48 hours. It depends on the adhesives you use and the drying systems and tools and also of design you use.

How much is a 50 lb bag of thinset?

The price is not the same in every store, but it varies from $10 to $25.

Is thinset waterproof?

Thinset mortars are waterproof tools, which means they can be used in damp environments like showers or outside. That makes them very technical.