Free estimate — verify against local code before building
Tile Calculator
Tile count, boxes, thinset, and grout by tile size and joint width.
What this calculator includes
Enter the area, actual tile dimensions, joint, waste allowance, and the package information printed on the selected tile. The calculator separates raw geometry, waste-adjusted tile count, whole-box rounding, and editable mortar, grout, underlayment, and spacer yields. It is a quantity takeoff—not an installation-system, substrate, waterproofing, movement-joint, or mortar-selection design.
How to use this tile calculator
- 01
Measure the area
Measure length and width in feet. For L-shaped rooms, split the floor into rectangles, run each one, and add the tile counts together.
- 02
Pick the tile and joint
Use the actual tile dimensions and the joint approved for the selected tile, grout, pattern, and installation. Calibrated versus pressed products and substrate flatness affect the choice.
- 03
Set the waste factor
Use 10% only as an editable starting point. Pattern, room shape, cuts, breakage, selection, attic stock, and product availability determine the appropriate allowance.
- 04
Check tiles per box
Enter either tiles per box or square feet per box from the selected product. Whole-box rounding is kept separate from the estimated whole-tile quantity.
Calculation sources and review
Primary references and formula assumptions are linked so you can verify them against the selected product, supplier, and adopted local requirements.
Internal formula review completed July 13, 2026. What this review covers
- TCNA Handbook for Ceramic, Glass, and Stone Tile Installation (opens in a new tab)
Industry installation methods, material selection guides, substrate preparation, movement joints, and workmanship references.
- CUSTOM Building Products VersaBond Coverage Chart (opens in a new tab)
Manufacturer coverage ranges by trowel, with jobsite and installation-practice limitations.
- MAPEI Tile Grout Calculator (opens in a new tab)
Manufacturer grout-estimating reference and warning that application and jobsite conditions change coverage.
- James Hardie Backer Board Product Guidance (opens in a new tab)
Manufacturer documentation and installation guidance for one optional tile underlayment system.
Frequently asked questions
How many 12×24 tiles do I need per square foot?
About one tile per 2 square feet — a 12×24 tile with a 1/8" joint covers 2.03 sq ft. A 120 sq ft floor with 10% waste takes about 65 tiles. Smaller tiles need more: a 12×12 covers just over 1 sq ft each.
How much extra tile should I buy for waste?
There is no single allowance for every project. Ten percent is a common planning start, but patterns, cuts, room geometry, breakage, visual selection, attic stock, and manufacturer guidance can require more.
What size grout joint should I use?
Use the tile and grout manufacturers' permitted range plus the applicable installation specification. Tile size variation, edge type, pattern, substrate flatness, movement accommodation, and grout formulation all matter.
How much does a 50 lb bag of thinset cover?
Coverage varies substantially by product, trowel, substrate, required mortar contact, angle, and technique. Enter the conservative coverage from the selected mortar's current technical data; the starting 45 sq ft value is not universal.
Do I need backer board under floor tile?
Not in every assembly. Subfloor structure, substrate, location, moisture exposure, waterproofing, crack isolation, deflection, and the selected installation method determine the underlayment. The calculator makes backer board optional; an approved assembly governs.