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BuildRight.DIY Calculators

Tile, Flooring & Decking Calculator

Count tiles, planks, deck boards and pavers — including grout joints, layout pattern waste and box rounding — then compare DIY material cost with a pro install.

1Measure the space

ft
in
ft
in

2Tile size & layout

in
in

Recommended: 10% for straight/offset, 15% for diagonal & herringbone.

3Packaging & price

sq. ft

Printed on the box. 0 = sold individually.

$

Your Porcelain Floor Tile estimate

Area incl. waste

132 sq. ft

120 sq. ft net + 10% waste

tiles needed

65

12" × 24" tiles

boxes to buy

9

16 sq. ft per box

Material cost

$504

$3.50 per sq. ft
Straight / Grid layout preview of 12" × 24" tiles in a 12' by 10' area12'10'
To-scale preview · Straight / Grid · 1/8" joints. Red hatching = thin sliver cuts.
DIY material vs. professional install
  • DIY — materials only$504
  • Installation labor (pro)$840 – $1,680
  • Hire a pro — total installed$1,344 – $2,184

Labor at $7–$14 per sq. ft (US average). Doing it yourself saves roughly $840–$1,680.

Material shopping list

Porcelain Floor Tile (12" × 24")65 tiles · 144 sq. ft purchased9 boxes
Thinset mortar (50 lb bags)≈ 50 sq. ft per bag with a 1/2" notch trowel3 bags
Sanded grout (25 lb bags)Approx. for 1/8" joints — check the coverage chart2 bags

120 sq. ft · Straight / Grid · 10% waste. Buy all boxes from the same lot.

How the flooring formula works

Pieces = ⌈ (Length × Width × (1 + Waste%)) ÷ ((Piece L + Joint) × (Piece W + Joint) ÷ 144) ⌉

  1. Measure the room: Length × width in feet = square feet.
  2. Choose a layout: Straight/offset: 10% waste. Diagonal/herringbone: 15%.
  3. Account for joints: (piece length + joint) × (piece width + joint) ÷ 144 = sq. ft per piece.
  4. Count pieces & boxes: Area with waste ÷ sq. ft per piece (or per box), rounded up.

Boxes are always rounded up to whole cartons, so the calculator also shows how many square feet you actually purchase — that's the number your material cost is based on.

Frequently Asked Questions

How do I calculate how much flooring I need?

Multiply the room length by width to get square feet, add 10% for waste (15% for diagonal or herringbone), then divide by the square feet per box printed on the carton and round up.

How much extra tile or flooring should I buy?

Buy 10% extra for straight and offset layouts, 15% for diagonal and herringbone, and up to 20% for small rooms with many corners. Keep a few spare pieces for future repairs.

Does grout spacing change how many tiles I need?

Slightly. Each tile effectively covers its own size plus half the joint on every side, so wider joints mean fewer tiles. The effect is biggest with small tiles like 3×6 subway or mosaics.

How do I avoid thin sliver cuts at the walls?

Start from a center line instead of a wall. Dry-lay a row in each direction and shift the layout so the cut pieces at both walls are at least half a tile wide.

Project-specific calculators