Tile Calculator

How many tiles do I need for a 10 by 10 room?

A room of 10 by 10 feet gives 100 square feet of floor while a 12 by 12 inch tile covers one square foot, which puts the bare coverage at 100 tiles before a single cut. The standard 10% allowance takes the order to 110 tiles, eleven boxes of ten with no spares left once the last row goes down. On the diagonal the same floor climbs to 115 tiles, so 12 boxes and 5 tiles kept back for repairs.

How to calculate square footage for tile

Square footage for a floor is the length in feet times the width in feet, while the area of one tile is its two sides in inches multiplied together then divided by 144, the number of square inches in a square foot. Dividing the room by the tile gives the raw count that a tile square footage calculator shows before the allowance goes on top.

In metric the sum runs in square metres, with the tile area in centimetres divided by 10,000, so a 5 by 4 metre room in 60 by 60 cm tile comes to 20 square metres and 56 tiles of coverage.

An L-shaped room comes out as two rectangles measured apart then added together. Thresholds in a doorway stay in the count instead of coming off it, the strip under a door still taking a cut piece. Grout joints do not come off the figure either, since a 12 inch tile actually measures a shade under 12 inches and the joint makes up the difference.

Tiles per 100 sq ft by tile size

The five formats below cover most residential work, from the 12 inch square used on bathroom floors to the 60 by 60 cm porcelain sold for open-plan rooms. Each row is what a tile sq ft calculator returns for a flat 100 square feet, first as bare coverage then with the 10% straight-lay allowance on top.

A large format looks cheaper in the count while costing more per mistake, one cracked 24 inch tile writing off four square feet of material against one for the small square.

How much extra tile should I buy for cuts?

A straight lay needs 10% extra and a diagonal or herringbone 15%. The straight version only loses material around the perimeter of the room, where whole tiles meet the wall and come back trimmed, which is the margin fitters and manufacturers both land on. Diagonal and herringbone layouts finish each row on a mitre cut, a 45 degree offcut that rarely fits anywhere else on the floor.

The result keeps those extra tiles on a line of their own: on the 10 by 10 floor, 10 tiles out of the 110 exist only to be cut up. An out-of-square room or a floor with several pipe cutouts earns another five points on top, which takes a 48 square foot bathroom from 53 tiles to 56.

How to calculate tile for a shower

Three walls of a 3 foot enclosure tiled 7 feet up go in once as 3 by 7 with the number of surfaces set to 3, which totals 63 square feet. In 12 by 24 inch tile that comes to 32 tiles of coverage, 35 tiles once the 10% margin is on and 5 boxes of eight, leaving 5 spares.

Walls of unequal width go in one at a time so that each one rounds up on its own, which is what separates a shower tile calculator from a single floor sum. A niche adds surface instead of removing it, its back and sides getting tiled too.

How many spare tiles should I keep?

One full box. The tiles left in the last opened box are the repair stock for the next ten years of the floor. Ceramic and porcelain take their colour in a dye lot, the production batch a tile was fired in. Shade drifts enough between lots that a tile bought two years later reads as a patch under raking light.

A count that lands on 0 spares, as the 110 tile floor does, is worth one more box at the counter, since ranges get discontinued inside a couple of years and a lost dye lot turns one cracked tile into a relaid floor.