Flooring and Tile Calculator

How to use the flooring calculator

1. Pick the flooring: laminate, vinyl plank, hardwood, tile or carpet, and for everything but carpet the layout (straight, diagonal, herringbone or chevron). Carpet can also go on stairs, and tile on walls.
2. Enter each area's length and width. Type feet and inches as 12'6" or metres as 3.8. Tick L-shaped for a room with a corner missing and give that corner's size. Add an area for each room, hallway or closet.
3. Fill in the product: the coverage per box from the label for planks; the tile size, grout joint and thickness for tile; the roll width for carpet.
4. Check the waste allowance. It starts at the maker's figure for the floor and layout you picked (the line under the field says whose).
5. Read the order. The big figure is what to buy: boxes, tiles or a length of roll. Under it are the area with waste, planks or tiles, grout, and the cost if you typed a price.

Everything runs in your browser and your rooms are kept here for next time. Share result makes a link that opens the same floor and order for someone else, and Copy order list puts the figures on your clipboard to take to the shop.

How it is worked out

Area is length × width, less the cut-out corner of an L-shape. For planks, boxes = area × (1 + waste) ÷ area per box, rounded up; with a plank size it also estimates the planks. For tile, each tile covers its own size plus one joint in each direction, so tiles = area × (1 + waste) ÷ ((length + joint) × (width + joint)); with the tiles per box you get whole boxes. A 12 × 15 ft room is 180 sq ft; with 10% waste that is 198 sq ft, which is 10 boxes of 20 sq ft.

Grout uses the formula in Mapei's data sheets, (A + B) ÷ (A × B) × C × D × 1.6 kg per m², with the tile's length A, width B and thickness C and the joint width D in millimetres. Small tiles and wide, deep joints use much more: 10 × 10 cm tiles 7 mm thick with 5 mm joints take 1.1 kg per m², while 60 × 60 cm tiles 10 mm thick with 2 mm joints take about 0.1. Custom Building Products points out that a joint just 1/32 in wider than planned on a 1/8 in joint needs 25% more grout, so round up to whole bags.

Waste allowance

The waste allowance covers, in Pergo's words, "cutting, installation errors and variation in floor design". The makers' figures the calculator starts with, as of September 2026:

• Laminate: 10%, from Pergo's project planner, and 15% laid diagonally.
• Vinyl plank: 10% for a standard installation and 15% for diagonal, from LifeProof's and Daltile's installation guides.
• Hardwood: Bruce's installation instructions: 5% on a straight lay, 10% on a diagonal one, more when solid wood is glued.
• Tile: 10%, from Daltile, which recommends buying about 10% more tile than you need, and 15% diagonal.
• Herringbone and chevron: no percentage. The pattern is laid over each area at your board size and the cuts are counted one by one, with left and right (A and B) boards kept apart. Chevron takes the cut angle too: 45°, 60° or 62.5°. See the herringbone page and the chevron page.

Small rooms waste proportionally more than big ones: Armstrong's estimating guide for resilient tile allows 14% up to 50 sq ft but 5% for 300 to 1,000 sq ft. Raise the allowance for a small bathroom or a hallway with many doors. Daltile also suggests keeping spare tile for repairs, and Cormar warns that carpet bought at different times may not match in colour, so buy everything at once.

Carpet

Carpet is cut from a roll of fixed width, so the question is how long a piece to buy. Shaw says most carpet is made in 12 ft rolls, with 15 ft also available; Cormar sells 4 m and 5 m widths in the UK and recommends planning a room from one width. The calculator lays strips across the room, each the room's length plus the extra for trimming, tries both directions (and both ways of splitting an L-shape) and picks the one that needs the least roll. It shows the length, the strips and seams, and the offcuts, which a fitter may use for a closet or a step.

Stairs, walls and hardwood

Choose carpet, then Stairs, to cut a flight from the roll: each step's piece runs down the stairs with the pile, several fit across the width of the roll, and the drawing shows where each one comes from. A runner gets its length instead. The stair carpet page explains the allowances. Choose tile, then Walls, to set out tiles row by row on walls with windows and doors, with adhesive, grout and edge trim (wall tile page). Hardwood adds the fitting: nail-down fasteners, glue by the pail or underlay, and the expansion gap to leave at the walls (hardwood page).

More for the same rooms

• Draw the room first in the 3D room planner: the calculator offers to add its floor.
• Painting as well? The paint calculator takes the same rooms and works out paint, primer and cans.
• Planning a tiled pattern or a furniture layout on paper? Print graph paper and draw one square per foot or per 25 cm.

Sources, checked September 2026: Pergo, Wood and Laminate Flooring Project Planner; Bruce, solid hardwood installation instructions; LifeProof, Vinyl Plank Installation Instructions; Daltile, ProSeries rigid core installation guide and FAQs; Mapei, Keracolor GG data sheet (grout formula) and Ultracolor Plus data sheet (consumption table); Custom Building Products, TB89 grout coverage rates; Armstrong Flooring, Guaranteed Installation Systems, Estimating; Shaw Floors, carpet installation planning; Cormar Carpets, planning and measuring.