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Tile Calculator

Work out how many tiles, boxes and how much thinset your floor or wall needs — with the right waste allowance for your layout.

Tile Calculator

Tiles, boxes and thinset needed for any floor, wall or backsplash — with layout-based waste.

How this is calculated

Tiles = (net area × (1 + layout waste)) ÷ tile area, rounded up. Boxes = tiles ÷ tiles per box. Thinset coverage depends on tile size (≈ 100 ft² per 50 lb bag for small tile down to ≈ 45 ft² for large-format).

Enter the room size (or total area), your tile size and layout pattern. The calculator adds the right waste for the layout (straight, diagonal, herringbone…), rounds up to whole boxes, estimates thinset mortar and totals the cost.

Results are estimates for planning purposes only. Real-world quantities depend on site conditions, materials and workmanship. Always verify measurements, follow local building codes and confirm quantities with your supplier or a qualified professional before ordering or building.

About the Tile Calculator

Running out of tile mid-project is one of the most expensive remodeling mistakes, because a second batch can come from a different dye lot and never quite match. This calculator sizes floor and wall tile jobs so you buy enough the first time: exact tile count, boxes to purchase and thinset bags, with the waste percentage matched to your layout pattern.

How to use

  1. Enter the length and width of the area to tile. For walls, use total wall area minus large openings like windows.
  2. Enter your tile size — for example, 12 by 12 inches for floor tile or 3 by 6 inches for subway tile.
  3. Enter how many tiles come in one box, printed on the box label, so the result rounds up to whole boxes.
  4. Choose your layout: straight, offset or diagonal/herringbone. Angled patterns need more cuts, so waste rises automatically.
  5. Buy the full box count at once, all from the same lot number.

Understanding your results

The tile count is the exact number of tiles needed including waste. The box count rounds that up to whole boxes — the number you actually buy. The thinset estimate tells you how many mortar bags to get, with coverage adjusted for trowel size.

How the calculation works

Room area is divided by the area of one tile (length times width, in square feet) to get the exact count. A waste factor is applied: 10 percent for straight and offset layouts, 15 percent for diagonal or herringbone. Boxes are the waste-adjusted count divided by tiles per box, rounded up. Thinset runs about one 50 lb bag per 50 to 80 square feet.

Tile Calculator FAQs

Buy 10 percent extra for straight and offset layouts, and 15 percent for diagonal or herringbone patterns where angled cuts waste more. Small rooms and hallways with many cuts deserve the higher end of the range. Keep a few leftover tiles after the job — they are invaluable if one cracks years later and the line is discontinued.
It varies by tile size and manufacturer, so always check the box label — that is the number the calculator asks for. As a rough guide, boxes of 12×12 floor tile often hold 10 to 12 tiles, covering about 10 to 12 square feet. Large-format 24×24 boxes may hold only 4 tiles. Never guess: two boxes of the same tile from different brands can hold different counts.
A 50 lb bag of thinset covers roughly 50 to 80 square feet, depending on trowel notch size. Large-format tiles need a bigger trowel (half-inch notch) and therefore more mortar per square foot, while mosaics need less. For a 100 square foot floor with standard 12-inch tile, plan on two 50 lb bags plus one spare.
Yes, if the existing tile is firmly bonded, level and clean — check for hollow spots by tapping. Roughen glossy surfaces so the thinset grips, and remember the new layer adds about half an inch of height, which can cause problems at doors, transitions and toilet flanges. Cracked or loose old tile must come up first.
Grout coverage depends on tile size and joint width, not just area. A 25 lb bag of sanded grout covers roughly 150 to 200 square feet for standard 12×12 tiles with 1/8-inch joints, but small mosaics or wide joints can cut that coverage in half. Wider joints and smaller tiles mean more grout per square foot.
Nabil Sharif, founder of CalcDune

Written by

Nabil Sharif

Founder of CalcDune — a free library of 137 online calculators for finance, health and everyday math. Every calculator shows the formula behind its result, so you can see exactly how your numbers are worked out.

More articles by Nabil →

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