WheelbarrowMath

Tile Calculator

Work out how many tiles and boxes you need, plus thin-set and grout, for a floor, backsplash, or shower wall.

Floor or wall to tile
  1. Area 1
    ft
    ft

For an odd shape, split it into rectangles, circles, and triangles; they're added together.

Tile size
in

Use the joint width the tile maker recommends. 1/8 in is 0.125; 1/16 in is 0.0625.Use the joint width the tile maker recommends, usually 0.15–0.3 cm (1.5–3 mm).

in

It's on the box. 3/8 in is 0.375.It's on the box. Most floor tile is 0.8–1 cm thick.

Layout
%

Lowe's suggests 10% extra. Angled layouts need 10–15%.

sq ft

It's printed on the box or product page.

Trowel notch
sq ft

CUSTOM VersaBond covers about 90–100 sq ft per bag with a 1/4 × 1/4 in trowel, 60–67 with 1/4 × 3/8 in, and 42–47 with 1/2 × 1/2 in.CUSTOM VersaBond covers about 8.4–9.3 m² per bag with a 6 × 6 mm trowel, 5.6–6.2 with 6 × 10 mm, and 3.9–4.4 with 12 × 12 mm.

Prices (typical US prices; edit for your area)
/sq ft

Tile and setting materials typically run $2–$30 a sq ft.Tile and setting materials typically run $22–$320 a m².

Your Results

Calculating …

How Much Tile Do I Need?

Tiles = area in sq in ÷ ((tile length + joint) × (tile width + joint))

Add 10% for cuts (more for angled layouts), round up, then round up again to whole boxes.

Worked example. An 8 × 10 ft bathroom floor is 80 sq ft. With 12 × 24 in tiles and 1/8 in joints, that’s 39.4 tiles; with 10% extra, 44 tiles, or 88 sq ft. At 15.5 sq ft a box you need 6 boxes (93 sq ft). Add 2 bags of thin-set with a 1/4 × 3/8 in trowel and about 4.3 lb of grout, which is one 25 lb bag.

Thin-Set by Trowel Size

The trowel notch sets how much mortar goes under each tile, and bigger tiles need bigger notches to get full contact. CUSTOM Building Products lists this coverage for its VersaBond mortar:

Trowel (square notch)Coverage per 50 lb bag
1/4 × 1/4 in90–100 sq ft
1/4 × 3/8 in60–67 sq ft
1/2 × 1/2 in42–47 sq ft

CUSTOM calls for at least 80% mortar contact in dry areas and 95% in wet areas and outdoors, and says large tiles and stone may need back-buttering. Always follow the directions on your mortar bag.

How Grout Is Worked Out

Grout fills the joints, so the calculator works out the joint volume: the length of joint per tile, times the joint width, times the tile thickness. It converts that to pounds with a density matched to CUSTOM’s Polyblend Plus sanded grout chart, which lists, for example, 348 sq ft per 25 lb bag for 12 × 12 × 3/8 in tile with 1/8 in joints.

CUSTOM also notes that joints just 1/32 in wider than planned use 25% more grout, so it’s worth rounding up.

Waste and Layout

  • Straight and offset layouts: about 10% extra (Lowe’s).
  • Diagonal and herringbone: 10–15% extra for the angled cuts (Mullican Flooring’s guidance for angled installs).
  • Small rooms: a larger share of tiles get cut, so lean toward the higher number.

Frequently Asked Questions

How Much Extra Tile Should I Buy?

Lowe’s suggests 10% extra for cuts and breakage. Diagonal and herringbone layouts make more angled cuts, so plan on 10–15%. Keep a few spare tiles for repairs; later batches may not match.

How Many Bags of Thin-Set Do I Need?

It depends on the trowel. CUSTOM’s VersaBond covers about 90–100 sq ft per 50 lb bag with a 1/4 × 1/4 in square-notch trowel, 60–67 sq ft with 1/4 × 3/8 in, and 42–47 sq ft with 1/2 × 1/2 in.

How Much Grout Do I Need?

Grout fills the joints, so it depends on tile size, tile thickness, and joint width. 100 sq ft of 12 × 12 × 3/8 in tile with 1/8 in joints takes about 7 lb; narrow joints and big tiles use much less.

How Much Does Tile Cost to Install?

HomeGuide puts installed tile at about $10–$50 a sq ft, with labor at $8–$20 a sq ft and materials at $2–$30.

Sources

Prices are national ballparks checked October 2026. Local prices vary.