How do I calculate how much tile I need?

Measure the surface in feet, enter the tile size in inches, choose a layout and enter tiles per box. The calculator estimates tile count, adds waste and rounds up to whole boxes.

How much extra tile should I buy?

This calculator uses 10% for straight grid, 12% for running bond, 15% for diagonal and 18% for herringbone. Pattern matching, complex cuts or future repairs may need more.

Can I calculate a full bathroom at once?

No. Estimate each floor or wall surface separately. Doors, windows, niches and alcoves should be subtracted before entry or handled as separate rectangles.

Does grout joint size affect tile count?

Yes. The calculator uses tile size plus grout joint to estimate the layout grid, so wider grout joints slightly reduce the number of tiles needed for a given area.

How is thinset estimated?

Thinset bags are estimated from surface area and the coverage per bag you enter. Final coverage depends on trowel size, substrate flatness, tile size and mortar product.

How is grout estimated?

Grout is estimated from a pounds-per-square-foot rate for quick planning. Use the grout manufacturer's calculator for final purchasing, especially with wide joints or textured tile.

Can I use this for backsplash tile?

Yes. Enter the backsplash length and height in feet, tile size in inches and the number of tiles per box.

Tile Calculator

Estimate tiles, boxes, square footage, waste, thinset, grout and material cost for one rectangular floor, wall or backsplash surface.

Surface dimensions, ft

Length

Width / height

Tile size, in

Tile length

Tile width

Grout joint, in

Installation pattern

Tiles per box

Thinset coverage, sq ft/bag

Grout, lb/sq ft

Price per box, $

Estimated purchase

9 boxes · 87 tiles

Layout preview · 10 x 8 tiles

Surface area

80 sq ft

Tiles before waste

With waste +10%

87 tiles

Purchased area

90 sq ft

Tile area

1 sq ft

Thinset

2 bags

Grout estimate

9.6 lb

Grid

10 x 8

Tile shade, box coverage, grout, thinset, substrate prep, and wet-area waterproofing depend on the actual product and installation conditions.

What the tile calculator estimates

This calculator estimates tile for one rectangular surface: a floor, wall, backsplash, shower wall or separate bathroom section. It returns tile count, boxes to buy, purchased area, thinset, grout and material cost.

Enter the surface length and width or wall height in feet.
Enter the tile length, tile width and grout joint in inches.
Choose a layout pattern to apply a waste allowance.
Enter tiles per box, thinset coverage and price per box when you need a buying estimate.
Review tiles, boxes, square feet purchased, thinset bags and grout pounds.

Whole bathrooms, multiple walls at once, doors, windows, niches and tub aprons are not separate inputs. Estimate each surface separately or prepare a net rectangular area before using the tool.

Tile calculation formulas

The model calculates the surface area, estimates how many tile positions fit the area using tile size plus grout joint, adds layout waste and rounds to whole boxes.

A = L \cdot W

A - surface area, L - surface length, W - surface width or height.

A_{tile} = \frac{( l + j ) ( w + j )}{144}

A tile - layout area per tile in square feet, l and w - tile sides in inches, j - grout joint in inches.

N = ⌈ \frac{A}{A _{tile}} ⌉

N - tiles before waste, A - surface area, A tile - layout area per tile.

N_{order} = ⌈ N \cdot (1 + \frac{r}{100}) ⌉

N order - tiles to buy, N - base tile count, r - waste allowance percent.

B = ⌈ \frac{N _{order}}{n _{box}} ⌉

B - boxes to buy, N order - tiles to buy, n box - tiles per box.

Purchased area is based on the clean tile size, while layout count uses tile size plus grout joint. That is why the two numbers may not match exactly.

Layout waste

The calculator applies a built-in waste allowance from the selected layout. Fragile large-format tile, patterned tile, shower niches or diagonal cuts may require more than the default estimate.

Layout	Waste used	Typical use
Straight grid	10%	Simple floor, wall or backsplash with square joints.
Offset / running bond	12%	Rectangular tile with staggered rows.
Diagonal	15%	More perimeter cuts and visual alignment loss.
Herringbone	18%	Pattern layout with more cuts and sorting.

Common US tile sizes

Tile size	Typical use
3 x 6 in	Subway tile backsplashes and walls.
12 x 12 in	Small floors and simple wall layouts.
12 x 24 in	Bathrooms, floors and shower walls.
18 x 18 in	Floor tile with fewer grout lines.
24 x 24 in	Large-format floors.
6 x 36 in	Wood-look plank tile.

Bathrooms, walls and backsplashes

This is a single-surface tile calculator, not a full bathroom takeoff. A shower wall, bathroom floor, tub surround, niche return and backsplash should each be estimated as its own rectangular surface.

Estimate each wall separately using wall length and tile height.
Estimate the floor separately because it often has a different tile size and layout.
Doors, windows, niches, benches and tub aprons are not subtracted automatically.
If you need net area, subtract openings first or split the surface into simple rectangles.
Buy boxes from the same dye lot or production lot when the finish needs to match.

For waterproofing, movement joints, shower pans and substrate preparation, follow the tile manufacturer's instructions and industry installation guidance. This calculator only estimates material quantity.

Thinset, grout and boxes

Thinset is estimated from the coverage you enter in square feet per bag. Grout is estimated from pounds per square foot, which is a simplified buying model for quick planning.

Result	How to read it
Boxes	Rounded up from tiles to buy and tiles per box.
Waste	A built-in layout allowance, not a manual percent field.
Thinset	Bags rounded up from surface area and the bag coverage you enter.
Grout	Approximate pounds from area and grout rate; use a manufacturer calculator for final purchase.

Large-format porcelain, uneven substrates and specialty mortars can change thinset coverage. Use product data sheets for the final bag count.

Limits and common mistakes

The calculator is not a 3D layout planner and does not choose decorative borders, accents or pattern repeats.
One input set equals one rectangular surface, not a whole room with every wall.
Openings, alcoves, shelves and plumbing penetrations are not separate fields.
Box count is approximate if the actual tile box contains a different quantity than the entered value.
Waste, thinset and grout remain buying estimates; jobsite coverage depends on substrate, trowel, tile back, product and installer technique.

Use the tile, mortar and grout manufacturer instructions for warranty-sensitive work. Industry handbooks help with installation standards, but product coverage still comes from the specific bag or box.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: June 2, 2026

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