Tile Square Footage and Grout Calculator
Calculate how many tiles you need and how much grout to purchase for your tiling project, including a waste allowance.
Formulas Used
Room Area (sq ft):
Room Area = Length × Width
Tile Area (sq ft):
Tile Area = (Tile Length / 12) × (Tile Width / 12)
Tiles Needed (with waste):
Tiles = ⌈ (Room Area / Tile Area) × (1 + Waste% / 100) ⌉
Grout Quantity (lbs) — TCNA Industry Formula:
Grout (lbs) = [(TileL + TileW) / (TileL × TileW)] × JointWidth × JointDepth × 144 × RoomArea × 0.09
Where TileL, TileW, JointWidth, JointDepth are in inches; RoomArea in sq ft; 144 converts sq ft → sq in; 0.09 = sanded grout density (lbs/in³).
Grout with Waste:
Groutfinal = Groutbase × (1 + Waste% / 100)
Assumptions & References
- Grout density of 0.09 lbs/in³ is standard for sanded grout (joints ≥ 1/8"). Use 0.085 for unsanded grout (joints < 1/8").
- Formula source: TCNA (Tile Council of North America) Handbook and standard tile industry practice.
- A 10% waste factor is the industry default for straight-lay patterns; diagonal or complex patterns typically require 15–20%.
- Grout coverage per bag varies by manufacturer — always verify against the product label.
- This calculator assumes a rectangular area. Subtract areas for cabinets, islands, or fixtures before entering dimensions.
- Tile counts are always rounded up to the nearest whole tile.
- Grout joint depth is typically equal to the tile thickness (usually 1/4" to 3/8" for floor tiles).