Learning how to calculate box fill correctly will ensure you meet building codes and reduce the risk of electrical fires. Use this calculator to help.
Thinset Calculator: How Much Thinset Do I Need?
No need to spread yourself too thin over thinset calculations
Get quotes from ceramic tile pros near you
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Get quotes from ceramic tile pros near you
No obligation · 100% free
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A thinset calculator helps you determine the exact amount of thinset you need by factoring in your tile size and total square footage.
Thinset coverage depends on your trowel size, with larger tiles needing deeper thinset layers and bigger trowels to ensure proper adhesion to the substrate.
You should match your trowel shape and size to your tile dimensions, as small tiles need shallow coverage while heavy tiles require thicker applications.
Hiring a local tile professional removes the guesswork from thinset mixing and application, ensuring your tiles bond properly and stay level throughout installation.
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Thinset is the adhesive used to glue tile to walls, and a proper calculation helps you stay under budget and prevent overpurchasing. There are a few steps to calculating how much thinset you need, but by following the guide and using the thinset calculator below, you’ll be able to arrive at a precise number.
How Much Thinset Needed to Properly Attach Tiles
Thinset is applied using different trowels designed to control the amount of product spread under each tile. The larger the trowel’s teeth, the deeper the grooves. For example, small tiles applied to smooth surfaces may only need a thinset layer 1/9 inch deep. This only requires a small trowel. Heavy tiles require a much thicker layer of thinset—1/4 inch or more—and a much larger trowel.
The table below is a general guide to help you estimate how many pounds of thinset to purchase. We recommend purchasing heavier, unmixed bags and mixing them yourself, as premixed thinset is much more expensive.
| Square Footage of Tiled Area | 1/9" Thinset Thickness | 1/4" Thinset Thickness |
|---|---|---|
| 10 | 7 lbs. | 18 lbs. |
| 20 | 13 lbs. | 36 lbs. |
| 40 | 27 lbs. | 73 lbs. |
| 80 | 53 lbs. | 145 lbs. |
| 120 | 80 lbs. | 215 lbs. |
Calculating Thinset Requirements
Photo: Dmitrii Balabanov / iStock / Getty Images Plus / Getty Images
When calculating how much thinset you need, start with the square footage and tile size. Once you know the tile size, consult the directions on the bag or product website where it tells you the coverage rate based on the trowel size. Common trowel sizes are 1/4 inch, 3/8 inch, and 1/2 inch.
A simple-to-follow order of operations is to:
Determine your total square footage you’ll be tiling
Decide which tile size to use
Find the coverage rate on the thinset you plan on using
Use the thinset calculator
Thinset requirements (in pounds) = (Area in square feet / bag coverage) x 1.08
The 1.08 at the end of the formula is a waste coefficient. This assumes you have no experience mixing and applying thinset. If you do—or believe you can work cleanly—change that number to 1.05.
Which Trowel to Use
Thinset application is determined by the tile you’re using. Thicker, larger tiles require more thinset to be added to the substrate—the wall you’re attaching the thinset to—and the larger the trowel needs to be. Determining the right trowel size is key to your tiles adhering properly.
There is another consideration: the trowel shape. There are U-notch, V-notch, and square trowels. U-notch trowels spread the least amount of thinset, then V-notch, with square leaving the most thinset on the substrate.
| Tile Size in Inches | Trowel Size in Inches | Trowel Shape |
|---|---|---|
| 4 | 1/4x1/4 | V-notch |
| 4–8 | 1/4x1/4 | Square |
| 8–16 | 1/4x3/8 | U-notch or square |
| 16+ | 1/2x1/2 | U-notch or square |
Differences Between Thinsets
There are two types of thinsets: modified and unmodified. The vast majority of home projects will use a modified thinset since it contains polymers like latex that add elasticity and strength to the cured paste. Modified thinset also shrinks much less than unmodified, leading to less cracking.
You might be wondering when it’s a better idea to use unmodified. If you plan on applying the thinset to an impervious surface, use unmodified since it requires moisture to cure.
Frequently Asked Questions
Ceramic tile services reviews from real Angi homeowners in Columbus, OH
4.6★ avg. • 42 total reviews
- Sue B.
Terrible experience. Walls/trim/floors/cabinets/doors all have drip marks, overspray, etc. Tiling at the fireplace had to be redone by another vendor due to incorrect and shoddy install by Profect. Contractor had his children in our house while he was on site without prior authorization or...
Profect painting & exteriors - Manoj K.
It was wonderful working with Yordy and his team. They were very professional and are experts in what they do. They have completed the work on time, with better quality and with in fairly reasonable price. We just started with backsplash work , but liking his work, we went on to provide...
Flooring Solutions - Bob T.
We were having 2”x 2” tile installed . There was a small installation error and the new additional replacement tile was from a different lot and the colors didn’t match. Joe assured us that he would rectify everything , which he did without hesitation. We decided to go with the 18” x 36” tile...
CarifaTile - Stephanie S.
For several months I was looking for somebody to tile a wall in my master bath and move lighting fixtures, and could not find anybody who was responsive. I contacted Rowe through Home Advisor and within days they came by to assess the job and provide an estimate. The cost was very...
Rowe House Development - Timothy C.
It went very well! The end product was amazing and we keep getting a lot of compliments from friends! M&E were very professional and they made sure we were happy with the product before leaving. They met with us in our home and at the tile shop to make sure we were okay with our tile and...
M&E Remodeling - Kendrick V.
Involved an extensive bathroom remodel, including removing tub & installing walk in shower, new drywall, custome tile work to ceiling, plumbing, etc. Overall, job was done on time and on budget. Nick & his team were very professional and had high attention to detail. Quality was great. Highly...
Stamos Flooring and Remodeling LLC - Locke M.
Very pleased with the service and level of professionalism. Courteous and very unobtrusive in performing service. Unlike several other companies, Bradford Xteriors was willing to perform work on a three story home with a clay tile roof. <br />
Bradford Xteriors - Jeffrey B.
This company did a very good job on the brick wall and it looks just amazing. The staff was always professional and was practically OCD on how the bricks were stacked and how they were laid. Although it took longer than expected, I am willing to sacrifice time over perfection anyday. The...
My Handy Mate LLC Improvement & Remodeling - Gary D.
He did the tile work and he was good at it. He used other subcontractors for the rest of the work (like putting in the cabinetry) and they were okay but not great. He was a great guy! He was easy to work with and had a good eye for the detail of his work. There were a couple of things that I...
Brian Miller Custom Remodeling - Michael S.
I was very impressed with Miller Cantrell! I live in an old home in which the sewage line that runs from my home to the sewage system is a line of clay tile. These eventually collapse and need to be replaced - an expensive problem and sure to happen at the worst time. I told them that my...
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