How to measure a room for materials
Five numbers drive every estimate: length, width, wall height, and the size and count of each opening. Here is how to take them once so every material can reuse them.
What you need
A tape measure (25 ft / 8 m), a notepad or your phone, and a few minutes. A laser measure is faster for long walls but not required.
1. Length and width
Measure the floor along each of two adjacent walls, wall to wall. Call the longer one the length. In the planner, Walls A and C are the length walls, B and D the width walls. Write the numbers in the form you measured them — 12' 6", 12 ft 6 1/2 in or 3.81 m are all accepted.
2. Wall height
Floor to ceiling. Measure at two places; use the larger. For a room with a sloped (gable) ceiling, the wall height is to the top of the wall where the slope begins, and you also need the rise: the vertical distance from the wall top to the ridge. The planner works out the true slope length — √((width ÷ 2)² + rise²) — so you never enter the slope yourself.
3. Openings
For each door and window: width, height, which wall it is on, and how many identical ones there are. Measure the rough opening. Write it next to the wall letter: "Wall B — window 48 × 48, 1". Openings are deducted from the wall they sit on; they never touch the floor area.
4. Floor exclusions
Anything the flooring will not go under — a built-in island, a fixed hearth — is a rectangle you subtract from the floor only. Measure its length and width.
5. Scope
Decide, wall by wall, what is being done. Boarding three walls and painting four is normal — the planner lets you tick each surface separately for each material, so your notes should say which walls are in which job.
Odd shapes
- L-shaped rooms: split into two rectangles.
- Gable ends: the triangle above a width wall has area ½ × width × rise. The planner can add both gable-end triangles as separate wall surfaces.
- Bay windows and alcoves: add each flat face as a custom rectangular surface.
- Known areas: if you already have a surface area from a plan, enter it as a known-area surface. It cannot provide edge lengths for trim or corner bead.
Worked set of numbers
Bedroom: 12' × 12', walls 9'. Door on Wall A 3' × 7'. Window on Wall B 4' × 4'. Scope: drywall and primer on three walls (A, B, C) and the ceiling; paint on all four walls; new flooring. Those notes are enough for the planner to produce the whole list.
Questions
Do I measure to the trim or to the wall?
Wall to wall, under any trim that will be removed. For openings, measure the rough opening (the hole in the wall), not the casing.
My wall height varies — which number do I use?
Measure at two or three points. For buying materials, use the largest; the small difference goes into the allowance.
How do I measure an L-shaped room?
Split it into rectangles. Each rectangle becomes its own room or custom surface in the planner, or add the areas and enter a known area.