Methodology

Tile

Floor area is the sum of the rectangles you enter. One tile covers its width and length plus one grout joint on each, converted from square inches to square feet:

coverage = (W + joint) × (L + joint) ÷ 144
tiles = ⌈ area × (1 + extra) ÷ coverage ⌉ · boxes = ⌈ area × (1 + extra) ÷ ft² per box ⌉

Default extra depends on the layout: 10% for straight and brick patterns, 15% for diagonal and herringbone, where more tiles are cut along the walls. This follows common installer practice; you can change it on every calculator.

Units and rounding

• Inputs in feet or meters; tile sizes in inches. 1 m² = 10.764 ft².
• Whole items you buy (tiles, boxes, gallons, sheets) are rounded up, never down.
• Areas are shown to one decimal, coverage per tile to three.

Testing before publishing

Each calculator ships with a written specification and an automated test suite: hand-worked examples (such as a 140 ft² L-shaped floor in 12×24 tile), plus property checks that more area never means fewer tiles and that the count always covers the area with the chosen extra. Results are compared against an independent calculator on several inputs before the page goes live, and the page cannot be published while a test fails.

When we get it wrong

Report it through the contact page with the numbers you entered. A confirmed error is fixed, turned into a new test case and noted with the date on the affected page.

Reviewed 2026-11.