Tile Calculator
Calculate how much tile you need while keeping net area, cutting allowance, tile size, product box coverage, and whole-box excess separate.
- Net tiled area
- 120 ft²
- Area with cutting allowance
- 132 ft²
- Tile-piece equivalent
- 132
- Whole boxes
- 9 × 15 pieces
- Purchased box coverage
- 139.5 ft²
- Excess after box rounding
- 7.5 ft²
Box coverage from the selected product controls the purchase result. This area estimate is not a tile layout or cut plan.
Show calculation
(12 × 10 ft − 0 ft²) × (1 + 10%) ÷ 15.5 ft²/box = 9 boxesTransparent method and editable product assumptions. Verify current labels and project requirements.
How this calculator works
This tile calculator multiplies surface length by width, then subtracts any area that will not receive tile. For an L-shaped room or several walls, calculate non-overlapping rectangles and combine their net area before final box rounding.
One editable cutting allowance is applied to net tiled area. The order area is divided by the square-foot coverage printed on the selected carton, and the result rounds up to a whole box. Actual tile dimensions provide an independent piece equivalent, but box coverage remains the purchase authority.
Grout joints, layout direction, pattern repeats, diagonal installation, edge cuts, shade lots, breakage, and spare stock can change the appropriate allowance. The default 10% is a transparent planning example supported by common retailer guidance, not a universal requirement.
Formula
Boxes = ceil{[(length × width − exclusions) × (1 + cutting allowance)] ÷ coverage per box}The live substitution appears with your result.Control example: 12 × 10 ft floor
The floor contains 120 ft². A 10% cutting allowance raises the order area to 132 ft².
At 15.5 ft² per box, 132 ÷ 15.5 = 8.52, so buy 9 boxes covering 139.5 ft².
Assumptions and limits
- The measured sections do not overlap.
- Excluded area will receive no tile from this order.
- Box coverage and pieces per box match the same current product.
- The cutting allowance covers layout cuts, breakage, and desired spares only once.
Common measuring mistakes
- Rounding each room to full boxes before combining areas using the same tile.
- Using nominal tile dimensions when the carton provides a different actual size or coverage.
- Subtracting grout-joint area from the carton coverage.
- Treating an area estimate as an optimized tile layout or edge-cut plan.
Sources
Product-specific values remain editable. These sources support the method and stated examples; they are not a universal substitute for your supplier’s current label.
- The Home Depot tile layout guide Supports length × width area, splitting L-shaped rooms into rectangles, and a typical editable 10% material allowance.
- Lowe’s SMARTCORE project planner Shows area × 1.10, division by carton square footage, and whole-carton rounding.
Questions people ask
How do I calculate how much tile I need?
Find net tiled area, add one cutting allowance, divide by the selected carton’s coverage, and round up to whole boxes.
How much extra tile should I buy?
Ten percent is a common starting point, but the appropriate allowance depends on pattern, room shape, cuts, breakage, matching lots, and spare-stock plans.
Should grout gaps reduce the tile order?
No. Use the carton’s published coverage. Grout-joint area is already part of the installed module and should not be deducted again.
Can I combine several rooms?
Yes, when they use the same tile and lot. Add their non-overlapping net areas, apply one allowance, and round boxes once.
Does this create a tile layout?
No. It estimates area, pieces, and boxes. Exact edge cuts, pattern alignment, and offcut reuse require a layout plan.