How to measure a room for flooring
Published
Every number on a flooring quote starts with the measurement. Measure low and you're a box short on install day; measure high and your price loses the job. This method works for any room: sketch it, split it into rectangles, measure each one carefully, and write down everything that changes the material list.
What you need
- A 25 ft or 8 m tape measure, or a laser measure for long rooms.
- A notepad or graph paper and a pencil.
- Your phone, for photos of doorways, vents, thresholds and anything you'll need to remember back at the office.
Step 1: Sketch the room first
Walk the room and draw its outline, roughly to shape. Mark doorways, closets, openings into other rooms, fireplaces, kitchen islands, floor vents and any change in floor height. The sketch keeps you from forgetting a closet, and it shows you where to split the room.
Step 2: Split it into rectangles
Most rooms are one rectangle or a few joined together. Draw lines on your sketch to split L-shapes, alcoves and bay windows into simple boxes. Closets are their own rectangles. Label each one (A, B, C) so your numbers match the drawing.
Step 3: Measure each rectangle wall to wall
Measure length and width at floor level, wall to wall. Walls are rarely perfectly straight or parallel, so measure each dimension in two places, near each end, and use the larger number. Round each measurement up to the next inch, or to the next centimetre if you work in metric.
While you're there, check whether the room is square: measure both diagonals of the main rectangle. If they differ noticeably, the walls aren't at right angles. That doesn't change the area much, but it matters for where you start the first row, and much more for diagonal and herringbone layouts.
Step 4: Convert to one unit and multiply
Multiply length by width for each rectangle, with both in the same unit. In imperial, convert inches to decimal feet by dividing by 12; the result is in square feet (sq ft). In metric, write each length in metres, so 397 cm becomes 3.97 m; the result is in square metres (m²). Add the rectangles together, then subtract anything the floor won't go under, such as a fireplace hearth or a fixed kitchen island.
Be careful with notation. 13 ft 10 in is 13.83 ft, not 13.10 ft. Writing 13.10 drops 0.73 ft, and on a 12 ft wide room that's 8.8 sq ft (0.82 m²) gone from the order. Metric has its own version: 4 m 5 cm is 4.05 m, not 4.5 m.
To convert between the two: 1 in = 2.54 cm, 1 ft = 30.48 cm, 1 sq ft = 0.0929 m² and 1 m² = 10.764 sq ft.
Step 5: Doorways, closets and transitions
Include the floor inside each doorway up to where the transition will sit, usually under the door when it's closed. Then count the transitions by type: to carpet, to tile, to a step down, at an exterior door. Each is a separate line on the quote, and they're easy to forget.
Step 6: Baseboard and trim
Baseboard (skirting board) and quarter round are sold by length. Measure the perimeter of the room and subtract doorways and anything else the trim won't run along, like a fireplace or built-in cabinets. Then add about 10% for miters and short pieces.
Worked example: an L-shaped living room, in feet and inches
Main area (A): 18 ft 4 in × 13 ft 0 in
Dining nook (B), off the long wall: 8 ft 6 in × 6 ft 9 in
Fireplace hearth, no flooring: 5 ft 0 in × 2 ft 0 in
A: 18 ft 4 in = 18 + 4 ÷ 12 = 18.333 ft. 18.333 × 13 = 238.33 sq ft
B: 8 ft 6 in = 8.5 ft; 6 ft 9 in = 6.75 ft. 8.5 × 6.75 = 57.38 sq ft
Hearth: 5 × 2 = 10 sq ft
Floor area: 238.33 + 57.38 − 10 = 285.71, call it 286 sq ft
Baseboard: for an L-shaped room, the perimeter equals the perimeter of the rectangle around it. That's 18.333 ft by 13 + 6.75 = 19.75 ft, so 2 × (18.333 + 19.75) = 76.17 ft. Subtract a 3 ft doorway and 5 ft of fireplace: 76.17 − 8 = 68.17 ft, about 68 ft.
Add 10% for cuts: 68.17 × 1.1 = 74.98 ft. In 8 ft lengths: 74.98 ÷ 8 = 9.37, so 10 lengths.
Transitions: one, at the doorway to the carpeted hall.
The same room in metric
Measured in metres and rounded up to the next centimetre: main area (A) 5.59 m × 3.97 m; dining nook (B) 2.60 m × 2.06 m; fireplace hearth 1.52 m × 0.61 m.
A: 5.59 × 3.97 = 22.19 m²
B: 2.60 × 2.06 = 5.36 m²
Hearth: 1.52 × 0.61 = 0.93 m²
Floor area: 22.19 + 5.36 − 0.93 = 26.62, call it 26.6 m². That's a little more than 286 sq ft converted (26.57 m²), because each length was rounded up.
Baseboard: the rectangle around the room is 5.59 m by 3.97 + 2.06 = 6.03 m, so 2 × (5.59 + 6.03) = 23.24 m. Subtract a 0.91 m doorway and 1.52 m of fireplace: 23.24 − 2.43 = 20.81 m.
Add 10% for cuts: 20.81 × 1.1 = 22.89 m. In 2.4 m lengths: 22.89 ÷ 2.4 = 9.54, so 10 lengths.
Those 286 sq ft (26.6 m²) are the starting point for the box count. How many boxes of flooring do you need? picks up this same room and works it through.
Common mistakes
- Forgetting closets. Open every door in the room before you start.
- Measuring one side only. A room that's 12 ft (3.66 m) at one end can be 12 ft 3 in (3.73 m) at the other.
- Mixing units. Write feet and inches, or metres and centimetres, on site, and convert at the desk. Never mix imperial and metric in one calculation.
- Ignoring height changes. A step down or a thick old floor next door changes which transition you need.
- Rounding the total instead of each measurement. Round each length up to the inch or centimetre, then calculate.
How Parquo does it
On iPhone Pro models from iPhone 12 Pro onward, Parquo scans the room with LiDAR, tracing walls and doorways as you walk it; on other iPhones you draw the room by hand. Either way, the measurements carry straight into the price: boxes, waste, underlayment, transitions and baseboard. It's still worth checking the longest wall with a tape before you quote, as covered in Measuring rooms with iPhone LiDAR.