How to use this calculator
- Enter the rectangular surface dimensions.
- Enter individual tile face width and height and grout joint.
- Add waste allowance, tiles per box, box price, and installation rate.
The calculation formula
Grid columns = ceil((surface width + gap)/(tile width + gap)); rows similarly; tiles = ceil(rows × columns × (1 + waste%)); boxes = ceil(tiles ÷ tiles per box).
Worked example
A 10 × 8 ft surface using 12 × 12 in tiles with 0.125 in grout has about 10 × 8 = 80 grid positions. With 10% waste and 10 tiles per box, plan 9 boxes.
Assumptions and limitations
- Tile quantity is a grid-based planning approximation, not a cutting diagram.
- Diagonal installation, irregular rooms, or breakage can materially change quantity.
Actual project costs may be affected by supplier rates, material grade, labor market, location, disposal, site condition, access, permits, taxes, and schedule. All entered prices are yours to revise. See our methodology and disclaimer.
Frequently asked questions
Should I buy partial boxes?
This estimate rounds up to whole boxes; check retailer return policies before ordering.
Do grout gaps reduce tile counts?
They affect layout spacing, but cutting rules and orientation also matter.