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Floor Tile Calculator

Quick answer: multiply the room’s length by its width in square feet, divide by the area of one tile and add 10% waste — 15% if you are laying diagonally, 20% for herringbone. The calculator below opens pre-set to 12×12 in tiles and returns tiles, boxes, grout, adhesive and cost in one pass.

Tile Calculator

Estimate tiles for any room, instantly.

Pick your units, enter your space, choose a tile. Everything updates live — no buttons, no waiting.

What are you tiling?
Units
Area to cover
Tile size
Layout pattern

Diagonal & herringbone add cutting waste automatically.

mm
%
Add box size & price

Used to estimate boxes needed.

Adhesive trowel

Bigger tiles usually need a deeper notched trowel.

Your Estimate

Live

Tiles needed

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0 boxes · covers 0 sq ft

Total area

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With waste

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Grout

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Adhesive

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How it works

How to Calculate Floor Tile

  1. Measure the room, not the tile

    Enter the floor length and width, then subtract any area you are not tiling. Measure at three points and use the largest reading - few floors are square.

  2. Pick the tile size and pattern

    Set the tile dimensions and grout gap, then choose the pattern. Large-format tiles and offset layouts change the waste rule, so set this before you read the total.

  3. Read tiles, boxes and cost

    The estimate returns tile count, box count, grout and adhesive, plus a cost total. Add 10% waste for a straight grid, 15% for offset and 20% for diagonal.

Measure the room in square feet, not the tile

The number that matters is the floor area: length times width, in square feet. Measure to the longest points of the room because old walls bow outward, and never measure the skirting — tiles stop at it. Once you have the area, theformula is simply area ÷ tile area, multiplied up by the waste percentage you set. For an L-shape, calculate each rectangle separately and add them.

Undercut doors, don’t tile around them

Cut the bottom of the door and its frame by the tile thickness plus 2 mm, then slide the tile underneath. You get one clean line instead of a U-shaped notch, the expansion gap stays hidden, and the door still clears the finished floor. Tiling up to the jamb leaves a cut so tight that it chips during fitting — the most common first-day mistake on a floor job.

Large-format tiles and patterns change the waste rule

Straight lay wants 10% extra, a diagonal layout 15% because every perimeter tile is a wedge, and herringbone or chevron 20–25% since the cuts at the walls are constant. Large-format tiles over 24 in also sit at 15%: one broken tile is a big slice of the order, and you cannot buy two replacements from a dye lot a year later. Choose the pattern in the calculator and the allowance is applied to tiles, boxes and grout together.

Transitions, thresholds and expansion gaps

Leave an 8–10 mm gap at every wall, at the threshold and around pipe penetrations, then cover it with beading or a transition strip. Ceramic needs the gap because it grows fractionally with temperature; vinyl planks need it more. Keep the perimeter tiles whole and centre the cut rows — set the room out first and the offcuts at the far wall stay visible rather than slivered. Projects in square metres convert with the unit switch, and everything here works the same way in anonline tile calculator.

FAQ

Floor tile questions, answered.

How do I calculate floor tiles for an irregular room?
Split the room into rectangles, calculate each one, then add them together. An L-shaped 12×10 ft room with a 4×4 ft notch is 120 − 16 = 104 sq ft. Divide by the area of one tile and add waste. The calculator takes a length and width per section, so you can enter the two rectangles separately instead of guessing at an average.
Should I undercut the door or tile around it?
Undercut the door and its jamb by the thickness of the tile plus a small gap. Sliding the tile underneath gives a clean edge with no awkward cut, and the door still clears the floor. Tiling around the jamb means a U-shaped cut on every piece that meets it, which never looks as good and usually breaks during fitting.
How much extra tile do I need for a patterned floor?
Straight lay needs 10%, diagonal 15%, herringbone and chevron 20–25%, and large-format tiles over 24 in also want 15% because a single broken tile is a large share of the order. Set the pattern in the calculator and the allowance is applied to the tile, box and grout figures together.
Does the floor tile calculator work in square metres?
Yes. Switch the unit control to m² and enter lengths in metres — the tile count, boxes, grout and adhesive all convert with it. Tile size presets cover metric as well, from 300×300 mm up to 600×1200 mm, so you are never mixing units in one calculation.
How much does it cost to retile a floor?
Fill in tiles per box and the price per box in the cost panel and the calculator multiplies boxes by price and adds grout and adhesive for a materials total. Tile is roughly half of an installed price, so use the figure as a budget for materials rather than a quote for the finished job.

Doing walls instead? Try themain tile calculator, the wall tile calculator, the shower tile calculator, or the bathroom tile calculator.