Flooring Calculator: How Much Flooring Do I Need?
Work out how much flooring a room needs in square feet and boxes, with waste for the layout, underlayment, trim and cost. Add each room and closet, pick the layout, and take the box count and the installed cost to the supplier or the quote.
Your numbers
Rooms
Up to 8 rectangles. Split an L-shaped room into two, and give each closet its own row.
Flooring
A label for your notes; the maths is the same.
Example value. Check the box label: it gives sq ft per carton.
A laminate maker's guide says to add up to 10 % for a straight lay.
Underlayment
100 sq ft is a common roll size. Check yours.
Trim and transitions
Typical, edit. Trim stops at each doorway.
Leave blank to use the room perimeters minus the doorways.
Typical, edit to what your supplier sells.
Typical, edit. Corners and mitres use some of each piece.
One at each doorway where the floor changes.
Prices
Optional. Applied to the floor area, without waste.
Boxes to buy
–
- Floor area
- –
- Area with waste
- –
- Flooring bought
- –
- Underlayment rolls
- –
- Trim
- –
- Material cost
- –
- Installation
- –
- Installed cost
- –
An estimate for quoting and ordering. Buy every box from the same lot, and keep a few planks for repairs.
The flooring maker's installation instructions decide the expansion gap, the underlayment and how the floor is laid.
The calculation runs in your browser and ParrotNotes does not store your numbers. They sit in the page address so you can bookmark or share the result.
How much flooring do I need?
Measure each room wall to wall in feet and multiply the length by the width. Split an L-shaped room into two rectangles, give each closet its own row, and add them up. Add the overage for your layout, divide by the square feet in one box and round up: you cannot buy part of a box.
Worked example: a 12 × 15 ft bedroom is 180 sq ft. With 10 % extra for a straight lay you need 198 sq ft; at 20 sq ft a box that is 9.9, so 10 boxes. Laid diagonally at 18 % it is 212.4 sq ft, or 11 boxes.
How much extra flooring to buy for each layout
Every cut at a wall leaves an offcut, and some planks arrive with defects you will not install. RW Supply + Design's laminate installation guide recommends adding up to 10 % to the order for a straight lay and 18 % when the planks run diagonal to the walls. Mercier's herringbone installation guide says herringbone orders should include about 15 % extra for cut loss, depending on the room. The calculator starts from those figures; change them to what your product's guide or your installer says.
Small rooms, hallways and lots of corners waste more. Buy every box from the same lot, and leave a few spare planks with the customer for repairs.
Underlayment, baseboard and transitions
Underlayment goes under the whole floor, so it is the floor area divided by what one roll covers; 100 sq ft rolls are a common size at home centres. Many vinyl planks and some laminates have the pad attached; then pick none, and follow the maker's instructions on whether anything else goes underneath.
Baseboard and quarter round follow the walls: the perimeter of each room minus the doorways. Add a little for corners and mitres and order whole pieces. Count a transition strip at every doorway where the new floor meets a different one.
Tips for the site visit
Measure each room on its own, closets included, and note what changes the job: the floor that has to come up first, a subfloor that needs levelling, the door casings to undercut, the stairs and the appliances to move. The flooring maker's installation instructions decide the expansion gap and how the floor is laid.
Then write down what the customer told you: the plank they picked, which way they want it to run, which rooms first and the date they move furniture back. Those notes decide the quote as much as the box count does.
Sources, checked October 2026. All figures are estimates:
More for flooring, building-materials and home-services sales: Building materials sales, Door-to-door sales, Construction daily report.
The box count is the easy part of the quote
The boxes go on the quote. What the customer said on the walk-through about the plank they picked, which way it runs, the old floor that has to come up, the stairs and the move-in date goes in ParrotNotes: record the visit and get the summary and next steps.
Get ParrotNotes freeRelated tools
- Tile CalculatorWork out how many tiles and boxes a floor or wall needs from the area and tile size, with grout gap, waste and cost.Open the tool
- Carpet CalculatorWork out how much carpet a room needs from 12 or 15 ft roll widths, with seams, waste, padding and the installed cost.Open the tool
- Square Footage CalculatorWork out square footage for rectangles, L-shaped rooms, triangles and circles, add rooms together, and convert to square yards, square meters and acres.Open the tool
- Unit Price CalculatorCompare prices per unit, per ounce, pound, liter or item, across up to four pack sizes or quotes and see which is the better buy.Open the tool