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Flooring & Tile Calculator
Work out how much flooring or tile to order: square footage with a waste allowance, the number of boxes and tiles, and an estimated material cost.
Your result
A planning estimate. Check it against the product label before you buy.
How the flooring calculation works
- Floor area = length × width, plus any extra areas you add, minus the areas that will not be covered.
- Waste allowance: the area is increased by the percentage you choose, to cover cuts at the walls, pattern matching and the occasional damaged piece.
- Boxes: the total is divided by the coverage printed on the carton and rounded up, because flooring is sold by the full box.
- Tiles: the total is divided by the area of one tile (length × width in inches ÷ 144) and rounded up.
- Cost: price per square foot × the amount you actually buy, in full boxes when a box size is entered.
A worked example
A 14 ft × 12 ft room is 168 sq ft. With a 10% allowance you need 184.8 sq ft. If each carton covers 22 sq ft, that is 8.4 cartons, so you order 9 (198 sq ft). At $4.50 per sq ft the material comes to $891.00.
Choosing a waste allowance
- 5%: planks or tile laid straight in a simple rectangular room.
- 10%: the common default: a normal room with a doorway or two and a closet.
- 15%: diagonal or herringbone layouts, large-format tile, or a room with many corners and cuts.
- 20%: complex patterns, or natural stone where pieces are sorted for colour and veining.
These are widely used planning allowances, not a rule. If the manufacturer or your installer gives a figure for the product and pattern, use theirs. Ordering everything at once also matters: boxes from a later production run can differ slightly in shade.
Rooms that are not rectangles
Split an L-shaped room into two rectangles. Enter the larger one as length and width, then put the area of the second in “Extra areas to add”. Measure at the widest points and round each measurement up to the next inch.
The cost shown is material only. Underlayment, adhesive or thinset, grout, trim, delivery and installation are not included, and the result is a planning estimate rather than a quote.
Questions about this calculator
How much extra flooring should I buy?
Ten percent is the common planning allowance for a normal room. Five percent can be enough for a straight lay in a simple rectangle; diagonal and herringbone layouts are usually planned at around fifteen percent. Follow the manufacturer or installer where they give a figure.
How do I calculate the square footage of a room?
Multiply the length by the width, both in feet. A room 14 ft long and 12 ft wide is 168 sq ft. For inches, divide by 12 first: 12 ft 6 in is 12.5 ft.
How many 12 × 24 tiles do I need for 100 square feet?
One 12 in × 24 in tile covers 2 sq ft, so 100 sq ft needs 50 tiles before waste. With a 15% allowance for a large-format tile, plan for 58 tiles.
Does the cost include installation?
No. The estimate is material only: price per square foot multiplied by the amount you buy. Underlayment, setting materials, trim and labour are separate.
One considered layer at a time.
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