How to measure a room

I have measured the same rooms more times than I like to admit, because I forgot a window or could not read my own notes. The order below is the one I ended up with.

1. Sketch the room first

Draw the room by hand before you measure anything. It does not need to be to scale. It only needs every wall, door and window on it, so that each number has a place to go.

2. Measure the walls

Start in a corner and work clockwise. Measure each wall along the floor, and write the number on the sketch before you move to the next. Use centimetres throughout, so you never wonder whether 3.4 meant 340 or 304.

If the wall is longer than the tape will stay taut, measure in two legs and add them up. A laser measure makes it easier, but you do not need one.

3. Measure doors and windows

For each door and window you need three numbers:

• the width of the opening
• the distance from the nearest corner
• for windows: the height from the floor to the sill

Note which way the door swings as well, and whether it is hinged on the right or the left.

4. Measure the height

Measure the ceiling height in at least two places. In older houses it can vary. If the room has a sloped ceiling, measure the height where the slope begins, and how far out over the floor it reaches.

5. Include what is fixed

Radiators, pipes, the chimney, the fuse box, sockets and switches. Measure where they are, and how much space they take. These decide whether the cupboard fits along the wall.

6. Check with the diagonals

Measure both diagonals, from corner to opposite corner. If opposite walls are the same length and the diagonals are equal, the corners are right angles. If the diagonals differ, the room is out of square, and the diagonal measurements are what let you draw it correctly.

Add up the partial measurements along a wall too, and check that the sum equals the whole wall.

In Plantekn: On a device that supports AR, you can measure the room from point to point with the camera. When you draw, the length is shown on each wall as you drag, so you see at once whether the drawing matches your notes.

Common mistakes

• Mixing metres and centimetres. Pick one unit and stick to it.
• Measuring some walls at the floor and others at chest height. Skirting boards and uneven walls give different numbers. Measure the same way throughout.
• Trusting that the room is square. Measure the diagonals.
• Forgetting to take photos. A photo of each wall answers the questions you did not know you would have.

Plantekn is a planning tool, not a surveying instrument. If the measurements will be used for something that costs money when they are wrong, measure twice.