Tile Calculator
Your estimate
Boxes9
- Area
- 80 ft²8.89 yd² · 7.43 m²
- Grout
- 5.7 lb2.6 kg
- Estimated cost
- $352
Floor or wall tiles of any size — tiles, boxes and grout with the joint width included.
Updated 2026-10-20 · Based on: coverage figures from paint and drywall makers (USG).
How to use the Tile Calculator
- Enter the floor or wall length and width.
- Enter the tile size and grout joint.
- Add 10 % waste (15 % for diagonal layouts or large tiles).
- Enter tiles per box to see the boxes to buy.
Formula
Tiles = area ÷ ((tile length + joint) × (tile width + joint)) × (1 + waste).
Grout = area × (tile length + width) ÷ (tile length × width) × joint width × tile thickness × 1.6 kg/l.
Worked example
With the values preset in the calculator above:
- Length
- 10 ft
- Width
- 8 ft
- Tile length
- 12 in
- Tile width
- 12 in
- Joint width
- 0.125 in
- Tile thickness
- 0.375 in
- Tiles per box
- 10
- Extra for waste
- 10 %
- Tiles (with waste)
- 87
- Boxes
- 9
- Area
- 80 ft² (8.89 yd²)
- Grout
- 5.7 lb (2.6 kg)
- Estimated cost
- $352
Tiles per square foot by size
- 12 × 12 in: 1 tile per ft²
- 12 × 24 in: 0.5 per ft²
- 6 × 24 in: 1 per ft²
- 18 × 18 in: 0.44 per ft²
- 4 × 4 in: 9 per ft²
Frequently asked questions
How many 12×12 tiles do I need for 100 sq ft?
About 100 tiles before waste, 110 with 10 % extra. With ⅛ in joints slightly fewer.
How much extra tile should I buy?
10 % for a straight lay, 15 % for diagonal or herringbone, and keep a few spare tiles for future repairs.
How much grout do I need?
For 80 ft² of 12 in tile with ⅛ in joints, about 5.7 lb.
More calculators
Estimates only — check quantities with your supplier and local building code before you order.