Formula
Tiles = area ÷ (tile length + joint) × (tile width + joint), plus extra for cuts. Boxes = (area × extra) ÷ coverage per box, rounded up.
How much extra?
- About 10% for straight layouts.
- About 15% for diagonal and herringbone patterns, which waste more at the edges.
- Keep a few spare tiles from the same batch for future repairs.
Frequently asked questions
How many 12×24 tiles for 100 sq ft?
About 50 tiles with no extra, or 55 with 10% for cuts (with a ⅛-in joint).
Last reviewed 2026-10-14. Estimates only — get written quotes from licensed local contractors before you decide.