A tile calculator turns the measurements of a room or wall into an exact tile count before you spend a cent. It divides the area by each tile’s surface, then builds in a waste allowance so cuts and breakage do not sink the job. DIYers tiling a first bathroom and contractors quoting kitchens use the same inputs: room size and tile size.
The result also shows total area, a figure you can reuse when estimating thinset, grout, and backer board for the same job.
The Formula and a Worked Example
The core method divides floor area by tile area, then rounds up. Packaging adds one more rounding step, since tiles per box varies with size and brand. Rounding each wall or section separately keeps totals honest when the room is not a perfect rectangle.
Take a 10 by 12 foot room, which is 120 sq ft. A 12 by 12 inch tile covers exactly 1 sq ft, so 120 tiles are needed bare. Adding 10 percent for cuts and breakage brings the order to 132 tiles.
Using the Inputs Without Overbuying
Choose Imperial (in, ft) or Metric (mm, cm, m), enter your space dimensions and tile size in the labeled fields, and press Calculate Tiles. The result fields show area size and tiles needed, already rounded up.
Order 10 to 15 percent extra for straight layouts and 15 to 20 percent for diagonal or herringbone patterns, keeping a few spares for future repairs. Also convert inches to feet early, because mixing units silently is the most common tiling estimate mistake.
Frequently Asked Questions
How much extra tile should I buy?
Budget 10 to 15 percent overage for straight layouts and up to 20 percent for diagonal patterns. That margin covers cuts, breakage, and keeping spares on hand.
How do I measure for wall tile?
Multiply each wall’s width by its height, add the walls together, then subtract windows and doors. Divide by tile area and round up to whole tiles.
How many 12×24 tiles per square foot?
One 12 by 24 inch tile covers exactly 2 sq ft, so a 100 sq ft floor needs 50 tiles before waste. Add at least 10 percent.
Is ceramic cheaper than porcelain tile?
Ceramic usually costs less per sq ft and cuts easier, while porcelain resists moisture and wear better. Cost differences still hinge on brand and finish.
How many tiles come in a box?
Coverage varies widely: a box might hold 10 to 12 large format tiles or dozens of 4 inch ones. Always order by quoted coverage in sq ft, never by tile count alone.