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Tile Calculator
Calculate how many tiles you need for any room — with automatic waste factor for straight or diagonal layouts. Results are rounded up so you're never short.
About This Calculator
Enter the room dimensions (feet) and tile dimensions (inches), choose a layout pattern, and instantly see how many tiles to buy — always rounded up and including the standard waste allowance.
How It Works
Room area (sq ft) = length × width. Tile area (sq ft) = tile width (in) × tile height (in) ÷ 144. Tiles needed = ⌈room area × (1 + waste%) ÷ tile area⌉. Straight-lay uses 10% waste; diagonal uses 15% because cutting on the bias generates more offcuts.
The Formula
tiles = ⌈(roomArea × (1 + waste÷100)) ÷ tileSqFt⌉ tileSqFt = (W_in × H_in) ÷ 144
- roomArea
- room length × width (sq ft)
- tileSqFt
- tile area converted to sq ft
- waste
- waste percentage (10% straight / 15% diagonal)
Frequently Asked Questions
- Why is diagonal layout 15% waste?
- Diagonal tile installation requires cutting corner tiles at 45°, which produces more offcut waste than straight grid patterns. The extra 5% accounts for this additional material loss.
- My tile is sold in boxes — how do I convert?
- Check the box for "sq ft per box" or "tiles per box." Calculate how many sq ft you need (tiles × tileSqFt) and divide by the sq ft per box, rounding up.
- Should I measure room area or floor area?
- This calculator computes floor area (length × width). For backsplashes or wall tile, measure the surface area directly.
Estimates only. Coverage figures (sq ft/gallon, bag yield, BTU/sq ft) are industry rules of thumb with real-world variance. Verify quantities with your supplier before purchasing.