Tile Flooring Calculator
Estimate floor tile by room size with a 12% waste allowance for cuts and breakage. Tile is sold by the square foot or by the box.
Tile Flooring calculator
How it's calculated: Room length ft × width ft = square feet, plus 12% waste for cuts and breakage. Tile is priced per square foot.
How to estimate tile flooring
- Use 10% waste for a simple grid, 15-20% for diagonal or herringbone patterns.
- Always order a little extra from the same lot - exact tiles get discontinued.
- Buy thinset, grout and backer board to match the same square footage.
- Dry-lay a row in both directions and shift the starting line so you do not end with thin slivers along a visible wall.
- Fix humps and dips in the subfloor before tiling - tile telegraphs every flaw, and lippage between large tiles is glaring.
Frequently asked questions
How much extra tile should I buy?
10% for straight layouts, 15-20% for diagonal or intricate patterns, plus a spare box for repairs.
How many 12x12 tiles do I need?
A 12x12 inch tile covers one square foot, so take the room's square footage plus 12% waste. A 120 sq ft room, for example, needs about 135 tiles.
Do I need backer board?
Over a wood subfloor, yes - cement board or an uncoupling membrane gives the thinset something stable to bond to. Tile bonded straight to plywood is a classic failure.
How do I estimate thinset and grout?
Both depend on tile size, joint width and trowel notch, so use the coverage chart printed on the bag. Bigger tiles need a deeper notch, which can roughly double thinset use compared with small tile.
Can I tile over existing tile?
Sometimes, if the old floor is solidly bonded and flat and you prep it for adhesion - but it raises the floor at doorways and under appliances. Removal is more work and usually the better job.