Tile Calculator
A complete tile installation requires tiles, thinset mortar, grout, and tile spacers — and the quantities of each depend on tile size, grout joint width, and room area. This calculator handles any tile size from 4×4 to 24×24 inches plus the popular 12×24 format, accounts for the grout joint width when calculating tile count (wider joints mean fewer tiles cover the same area), and estimates 25lb grout bags and 50lb thinset bags. Waste factor matters: straight lay needs 10%, offset brick pattern needs 15%, and diagonal layout needs 20% extra for angled cuts. Large-format tiles (18×18 and up) require a larger notch trowel (1/2" square notch) and reduce thinset coverage to about 30 sq ft per bag. Rectified tiles can use a 1/16" grout joint; natural stone and travertine typically use 3/16" to 1/4".
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How to Use This Calculator
- 1Enter your measurements in the fields above. Use the units shown next to each field (ft, in, etc.).
- 2Click Calculate to get your material estimate instantly.
- 3Review the highlighted result — it shows the key quantity you need to order.
- 4Use Copy Results to save your estimate, or bookmark the URL — your inputs are encoded in the link.
Pro tip: Always add 10% to your material order to account for waste, cuts, and defects.
Frequently Asked Questions
How many 12×12 tiles do I need for a 10×8 bathroom?
A 10×8 bathroom is 80 sq ft. At 1 tile per sq ft (12×12 inch), you need 80 tiles plus 10% waste = 88 tiles. Add 4 bags of 25lb grout and 2 bags of 50lb thinset mortar.
How much thinset do I need per square foot?
A 50lb bag of thinset covers about 40–50 sq ft for standard floor tiles with a 3/16-inch notch trowel. Large-format tiles (18×18 and up) need a larger notch and reduce coverage to about 30 sq ft per bag.
What grout joint size should I use for floor tile?
For rectified (precisely cut) porcelain tiles, a 1/16" joint gives a clean modern look. For standard pressed tiles, use 3/16" (the most common). For natural stone or travertine with irregular edges, use 1/4". Check the tile manufacturer's recommendation — some large-format tiles require a minimum 1/8" joint to accommodate manufacturing tolerances.
Can I tile over existing tile?
Yes, if the existing tile is firmly bonded (no hollow spots), the floor is structurally sound, and the added height won't cause issues with doors or transitions. Use a polymer-modified thinset and ensure the combined thickness doesn't create a tripping hazard at doorways. Check that the subfloor can support the additional weight — tile is heavy, and two layers add roughly 8–12 lbs per sq ft.