Can I make a floor plan from photos of the rooms?
Only partly. Photos remember what's in a room — but a photo without a known measurement in frame can't tell you how big anything is.
Short answer: No, not on their own. A photo carries no scale: the same living room can look 3 m or 5 m wide in a picture, depending on where you stood and how wide-angle the lens is. What photos are excellent at is memory — they show where doors, windows, recesses, radiators and sockets sit. Combine photos with 3-5 real measurements per room, and you can draw a properly measured floor plan at home without being in the house.
Why a photo can't measure
A camera projects a three-dimensional world onto a flat surface. In that process, depth disappears. It's the same reason tourist photos can make someone look like they're holding up the Leaning Tower of Pisa: the eye can't tell what's large and close from what's small and far away.
Two things make it worse in a home. The wide-angle lens estate agents use stretches the room out towards the edges, so an ordinary living room looks like a hall. And photo height — most people shoot from chest height, which makes the floor look shorter than it is.
The conclusion isn't that photos are useless. It's that a photo needs a known measurement in frame before it can be used for anything beyond memory.
How to make a photo usable: add a scale reference
If you have access to the room for five minutes, you can make your photos measurable afterwards:
- Lay an unrolled tape measure on the floor along one wall, so the numbers are readable in the shot.
- Take the photo as square-on to the wall as possible, and from the same height as the tape measure if you can.
- Note one certain measurement on the spot — say, the wall's full length — so you have an answer key once you're home.
With that one known length, you can work out the rest of the same wall: if the wall is 4.12 m and spans 2,060 pixels in the photo, 1 pixel equals 0.2 cm, and a window spanning 600 pixels becomes 1.20 m. This only holds for things in the same plane as the tape measure — not for anything set further back in the room.
What photos are genuinely good for
Photos solve what measuring alone can't: they remember the details. When you're sitting at the kitchen table redrawing the plan, it's not the figures you're missing — you've written those down. It's everything else:
- Which way the doors swing open.
- Whether the radiator sits under the window or beside it.
- Where the sockets and drains are.
- Whether there's a recess behind the door, a chimney breast in the corner, a duct in the bathroom.
- How the floor runs, and where the transition between two flooring types falls.
Take two shots from each corner of each room, plus one shot straight down each wall. That's 6-8 photos per room and takes under a minute. Nobody can remember a home in that much detail a week later.
What about apps that build 3D from photos?
Photogrammetry — building a 3D model from many photos taken from different angles — works, and apps exist for it. But the method relies on recognising the same points across several images, and a home is about the worst subject imaginable: large, smooth, single-coloured surfaces with no pattern. A white wall in a dimly lit room gives no points to recognise, so the geometry drifts.
That's exactly where LiDAR differs: the sensor measures distance with pulses of light rather than calculating it from the image, so it also works on a blank white wall and in a dark room. LiDAR sits in the Pro models of the iPhone and in the iPad Pro.
If you use a photo-based app anyway, always do this: measure at least one wall in each room with a tape measure and hold it up against the app's figure. If they agree within a couple of centimetres, you can trust the rest for that room.
The combination that actually works
The fastest route to a properly measured floor plan without a scanner isn't photos alone or a tape measure alone, but both in one pass:
- Walk one round with a tape measure. Per room: two internal sides corner to corner, the diagonal, the wall thickness in a door reveal, and the width and corner distance of doors and windows. Write it all in centimetres.
- Take 6-8 photos per room in the same round.
- Draw the plan at home with the figures as your answer key and the photos as memory. In HouseSense you drag out the rooms with your finger and type in the measurements in whole centimetres — the drawing follows the numbers, not the finger.
The maths you can follow along: a room measured at 4.12 m × 3.05 m has an area of 4.12 × 3.05 = 12.57 m², and if it's square, the diagonal should be the square root of (16.97 + 9.30) = 5.13 m. If you measure 5.21 m, the room is out of square — and no photo of the room can tell you that.
One thing neither photo, scan nor drawing can settle
Whether a wall is load-bearing. A picture of a wall says nothing about what it's holding up, and neither does a floor plan. If a wall is coming down, a building surveyor or an engineer needs to look at it on site.