15x15 Room Tile Calculator
225 sq ft — large living room or patio.
Open Tool →How Many Tiles Do I Need for a 20x20 Room?
A 20x20 room is 400 sq ft, a large span where slab flatness, garage transitions and long-run drift matter more than in a smaller room.
Instant answer: A 20x20 room covers 400 sq ft. With 10% waste, plan on about 440 sq ft of tile or roughly 110 24x24 tiles, 196 18x18 tiles, or 220 12x24 tiles.
What are you tiling?
Room size
This calculator is pre-filled for a 20 ft × 20 ft (400 sq ft) room. Change the numbers below if your room is a different size.
Tile size (inches)
Common sizes for this room (click to fill):
10%
10% default for an open floor · 15% for garage floor drain slopes · 20% for diagonal layouts
Tiles to Buy (incl. wastage)
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Tiles Without Wastage
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Area (sq ft)
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Area (m²)
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20×20 Room Tile Quantities by Format
| Tile Size (in) | Coverage / Piece | Estimated Quantity (10% Waste) | Recommended Application |
|---|---|---|---|
| 24×24 | 4.00 sq ft | 110 pieces | Expansive large-format porcelain; minimizes grout line maintenance |
| 18×18 | 2.25 sq ft | 196 pieces | Classic commercial and residential square grid format |
| 12×24 | 2.00 sq ft | 220 pieces | Dynamic 33% offset running bond for modern open-plan floors |
| 12×12 | 1.00 sq ft | 440 pieces | Traditional garage quarry tiles or heavy-duty floor grids |
400 Sq Ft FAQs
No. Never tile over active concrete expansion joints without honoring them in the tile layer. Use flexible silicone expansion sealant at slab joint locations to prevent tile cracking.
Select full-body unglazed porcelain or quarry tile with a PEI V rating. Ensure 100% thin-set mortar coverage beneath each tile to support vehicle weight without cracking.
Garages & Large Slabs: Control Joints and Heavy Loads
A 20×20 foot room (400 square feet) represents an expansive open footprint, typically seen in 2-car garages, basement rec rooms, open-plan great rooms, and light commercial spaces. Managing a 400 sq ft tile installation involves pallet-scale material handling, control joint alignment, and substrate deflection control.
- Concrete Control Joints: Never tile directly over existing concrete expansion joints. Mirror slab control joints through the tile layer using soft elastomeric sealant joints, or bridge non-structural hairline cracks using an uncoupling membrane (such as Schluter-DITRA or Laticrete STRATA_MAT).
- Vehicular Loads: For garage floors supporting vehicles or heavy machinery, select unglazed porcelain or quarry tile with a PEI rating of V and minimum 1/2-inch thickness. Achieve 100% mortar coverage using a 1/2-inch square-notch trowel with back-buttering.
- High-Performance Grout: Use epoxy grout (ANSI A118.3) or single-component high-performance grout for oil, chemical, and stain resistance in garage environments.
Pallet Logistics & Box Estimations
Pallet & Box Ordering: Tiles are packaged in boxes covering 10 to 15 sq ft (typically 30 to 45 boxes per 440 total sq ft target). When ordering 400+ sq ft, tile is shipped on full wooden pallets (approx. 1,800 to 2,200 lbs). Ensure all cartons share the same dye-lot and caliber codes before installation.
Mortar Requirements: Setting 400 sq ft of large-format tile requires approximately eight to ten 50 lb bags of modified thin-set mortar.