To work out how much flooring you need, measure the room in square feet or square metres, add 5 to 10 percent for waste (more for diagonal and herringbone layouts), then divide by the coverage on the box and round up. A 12 by 12 foot room is 144 square feet, so with 10 percent waste you need about 158 square feet, which is 8 boxes that cover 20 square feet each.
How much flooring do I need? The four-step formula
The same four steps work for any room and any floor:
- Measure the length and width of each section of the room and multiply to get its area.
- Add the sections together for the total area.
- Multiply the total by 1.05 to 1.15, which adds 5 to 15 percent for waste.
- Divide by the coverage printed on one box, then round up to a whole box.
Written as one line: boxes = total area x (1 + waste) / coverage per box. A flooring calculator does exactly this. You can run it on paper in a few minutes.
Many Ontario stores quote square feet, and some labels also show square metres. One square metre is about 10.76 square feet, so convert before you mix numbers.
Example: a 12 by 12 foot room (3.7 by 3.7 m) is 144 square feet (13.4 m²). With 10 percent waste, 144 x 1.10 = 158.4 square feet. If a box covers 20 square feet, 158.4 / 20 = 7.9, so you order 8 boxes.
How to measure a room, including odd shapes
- Sketch the floor plan and write each dimension on it. A phone photo of the sketch is handy at the store.
- Split odd shapes into rectangles. For an L-shaped room, measure the two rectangles and add them. For a triangle, multiply half the base by the height.
- Measure wall to wall. Floating floors leave an expansion gap at the walls, often around 10 mm (3/8 in) but set by the manufacturer, and baseboard or quarter-round covers it. You still count the full area.
- Include closets, alcoves, hallways and door openings. Run the area through each doorway to the middle of the opening or the threshold.
- Fixed cabinets and tubs. You can subtract the footprint of anything the floor will not go under, but most people leave it in, because cutting around cabinets uses extra material.
- Round up each measurement to the next 25 mm (1 in).
- Treat stairs separately. Treads, risers and nosings are cut and priced as pieces, so do not fold them into the room area.
Worked example: a living room of 3.7 by 4.9 m (12 by 16 ft) is 192 square feet. Add a hallway of 3 by 10 ft (30 sq ft) and a closet of 3 by 4 ft (12 sq ft) for 234 square feet. With 10 percent waste, that is 257.4 square feet, or 13 boxes at 20 square feet each.
How much extra flooring to buy: waste factors
Waste comes from cuts at walls, end pieces too short to reuse, boards with defects and the occasional mistake. These are commonly quoted rules of thumb. The flooring maker's installation guide and your installer's estimate come first.
| Layout or product | Typical waste to add |
|---|---|
| Straight lay, simple rectangular room (vinyl plank, laminate, engineered) | 5 to 10 percent |
| Hardwood, straight lay | About 10 percent |
| Many corners, closets or angles | 10 to 15 percent |
| Diagonal layout | 10 to 15 percent |
| Herringbone or chevron | 15 to 20 percent |
| Tile, straight lay | About 10 percent, more for large format |
For vinyl plank in a simple room, 5 to 10 percent is usual. Go higher where there are many cuts. Percentages also behave differently by room size. In a small room, 10 percent is only a few planks, so lean toward the higher end. In a large open basement, the same percentage is a lot of material, and a careful installer can reuse offcuts to stay near the low end.
How much flooring comes in a box, and how many boxes to order
Flooring is sold by the box, so the label sets your math. Look for coverage per box in square feet, square metres or both. Boxes of vinyl plank, laminate and engineered flooring often hold roughly 15 to 25 square feet, and tile boxes often cover less. Plank length, width and count vary, so use the label on the product you pick.
This table assumes 10 percent waste and 20 square feet per box:
| Room | Area | With waste | Boxes |
|---|---|---|---|
| 10 x 10 ft (3 x 3 m) | 100 sq ft | 110 sq ft | 6 |
| 12 x 12 ft (3.7 x 3.7 m) | 144 sq ft | 158.4 sq ft | 8 |
| 12 x 15 ft (3.7 x 4.6 m) | 180 sq ft | 198 sq ft | 10 |
| 15 x 20 ft (4.6 x 6.1 m) | 300 sq ft | 330 sq ft | 17 |
Swap in the coverage from your label. Change the layout and the answer changes. A herringbone pattern at 15 percent waste turns the 12 by 12 room into 165.6 square feet, which is 9 boxes.
How much hardwood or vinyl plank flooring to buy
Hardwood. Boards are graded, and lower grades carry more knots, colour variation and defects that get cut out. That is why 10 percent is a common starting point, and long narrow rooms or many doorways can push it higher. Hardwood also has to acclimatize to the house before installation, so follow the manufacturer's instructions and plan delivery around it. Buy the whole quantity at once so the boards come from the same production run.
Vinyl plank and laminate. Click-lock planks come with a stagger rule from the maker, which sets the minimum distance between end joints in neighbouring rows. A good installer starts the next row with the offcut from the last one, which keeps waste low. Rooms with many wall angles lose more. Check that the lot numbers on every box match, because colour can shift between production runs. Our luxury vinyl plank guide covers how the product is built.
Why a spare box matters
Treat the waste number as a minimum and keep what is left. A plank damaged by a dropped pan or a pet in three years is only easy to replace if you still have a matching one. Production runs differ, and lines get discontinued.
- Store spare planks flat, indoors and dry, in the original carton. A garage or unheated space with big temperature swings is a poor spot for vinyl or wood.
- Photograph the box label, with the product name, colour and lot number.
- Ask about the return policy for unopened boxes before you order. Policies and restocking rules vary by store.
Check a flooring quote against your numbers
A written quote should show the measured area, the waste figure, the product and box count, and what is not included, such as underlayment, transitions, removal of the old floor and subfloor work. If an installer's area is much larger than yours, ask why. Closets and doorways often explain it. Underlayment usually covers the same area as the floor, and transitions and stair nosings are counted by length, which is where a guide to floor transition strips helps.
A floor that is not flat or has moisture problems changes the job, so read our subfloor preparation guide before you finalize quantities. To see what moves the price, start with the flooring cost guide and the flooring buyer guide. D&D Interior Services starts every flooring installation with a free written quote that separates the visible finishes from plumbing, electrical and structural work, so you can compare it to your own numbers.
Flooring quantity questions
How much flooring do I need for a 12x12 room?
A 12 by 12 foot room is 144 square feet (13.4 square metres). Add 10 percent for waste and you get about 158 square feet. If a box covers 20 square feet, order 8 boxes. For herringbone or a diagonal layout, add 15 percent or more, which brings the same room to 9 boxes.
How much extra vinyl plank flooring should I buy?
For a straight lay in a simple room, 5 to 10 percent extra is usual. Add more for rooms with many corners, closets or angles, and for diagonal layouts. Keep the leftover planks as spares. Check your manufacturer's installation guide, because stagger rules affect how much you cut off.
How much hardwood flooring should I buy?
About 10 percent extra is a common starting point, because boards are graded and defects get cut out. Lower grades, long narrow rooms and diagonal or herringbone patterns need more. Buy all of it at once so the boards match, and follow the maker's acclimation instructions before installation.
How much flooring comes in a box?
It depends on the product, so use the coverage printed on the box label in square feet, square metres or both. Vinyl plank, laminate and engineered boxes often hold roughly 15 to 25 square feet, and tile boxes often cover less. Divide your total area plus waste by that number and round up.
How do I use a flooring calculator?
Enter the length and width of each section, your waste percentage and the coverage per box from the product label. The calculator multiplies, adds waste and divides by box coverage. Check that it rounds up to whole boxes. If the result looks off, test it against the paper formula.
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Get a Free Interior QuoteKey Takeaways
- Boxes = total area x (1 + waste) / coverage per box, rounded up.
- Add 5 to 10 percent for a straight lay, about 10 percent for hardwood, and 15 percent or more for diagonal or herringbone.
- Measure wall to wall, split odd rooms into rectangles and treat stairs separately.
- Use the coverage on the actual box label. A 12 by 12 room at 10 percent waste is 8 boxes of 20 square feet.
- Keep a spare box of the same lot for future repairs.
Plan your renovation
Select the room or finish you want to change and describe how you use the space.
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