Short answer. A phone can measure a room through its camera to within a few centimetres: good enough to plan furniture, not good enough to order a fitted kitchen. Measure in good light, from about a metre away, corner to corner at floor level, and check one wall with a tape measure. Write every size in one unit, then type the numbers into a floor plan or let a room-scanning app draw it for you.
Scan a room on AndroidStandard room sizesWill it fit through the door?
Which tool for which job
| Tool | Typical accuracy | Best for |
|---|---|---|
| Steel tape measure | About 1 to 2 mm | Fitted furniture, kitchens, doors, anything you order to size |
| Laser measure | About 2 to 3 mm | Long walls, high ceilings, measuring alone |
| Phone, measuring through the camera | A few centimetres | Planning furniture, quick checks, rooms you visit once |
| Phone, scanning a room corner by corner | A few centimetres | A whole room's shape and wall lengths in minutes |
The best plan uses both: the phone for the room, the tape for the one or two numbers that must be right.
What to measure
Each wall inside the room at floor level, clockwise from the door; doors (opening, swing, distance from the corner); windows (width, height, sill height); the ceiling height; radiators, pipes, chimney breasts and sockets; and both diagonals, because if they differ the room is not square.
Measuring with the phone's camera
- Light the room and let the phone find the floor by moving it slowly.
- Stand about 1 m (3 ft) away and mark the start exactly where the floor meets the walls.
- Walk slowly to the end point and mark it, phone steady.
- Measure twice; if the results differ by more than 2 cm (about 1 in), measure a third time.
- Check with something you know: an A4 sheet is 29.7 cm (11.7 in), a US letter sheet 11 in (27.9 cm).
It goes wrong on plain white walls and shiny floors, in dim light, over long distances (a small tilt becomes centimetres over 5 m), at the top of the skirting instead of the floor line, and when you move fast.
Recording the numbers
Pick one unit and stay with it: 1 in = 2.54 cm, 1 ft = 30.48 cm, 1 m = 39.37 in. Sketch the room first and write each size along its wall, going round clockwise from the door. Write 3.47 m, not "about 3.5".
Turning the numbers into a plan
Start with the largest room, type each wall's inside length, add the neighbouring rooms against its walls, then the doors and windows at their measured distances, the fixed things, and check the diagonals.
In Flatwalk you can draw the room and type each wall's length, or use "Scan your whole room": tap each floor corner through the camera, add doors and windows by aiming at their frames, and keep the room as measured or straighten it to square corners. Lengths show in metres, centimetres, or feet and inches, as you choose. In the 3D flat a tape measure reads any line, square to the wall, level or straight up; it measures the plan, so it is only as true as the sizes you gave it.
What Flatwalk does that older planners skip
Lights
Add ceiling lights, lamps and LED strips to the room you measured and see it lit.
Your flat in its city
Give the address and the street and buildings around you appear in 3D where the map has them.
Sun for your address
Real sunlight through the windows you measured, by date and hour.
One piece, in your own room
Through the live camera or in a photo of the room, stand a sofa on your own floor at its true size before you buy.
Detail
Dozens of door and window types, and kitchens, wardrobes and bathrooms built piece by piece.
Made for a thumb
Tap a wall and type its length; tap the start and end of a line to measure it.
Swipe for more. Every picture is the app itself.
One flat, free
Most people plan one home. For that, Flatwalk costs nothing: no trial clock and no card. Drawing, exact wall sizes, room scanning, the tape measure, furniture, lights, sun and walking are all part of it, and each AI tool gives one free try. A membership is for people who want more flats or more AI.
Questions people ask
Can I measure a room with my phone? Yes. Phones that support Google's or Apple's AR services can measure through the camera to within a few centimetres. Check one wall with a tape measure.
How accurate is measuring with a phone camera? Usually within a few centimetres in good light over short distances. Accuracy drops on plain surfaces, in low light and over long distances.
Is a phone accurate enough for a kitchen or fitted wardrobe? No. Use a steel tape or a laser measure for anything made or ordered to size.
Should I measure in centimetres or inches? Either, as long as you use one unit for everything. Many planning apps, Flatwalk among them, let you choose.
How do I turn room measurements into a floor plan? Start with the largest room, type each wall's inside length, add the neighbouring rooms against it, then the doors and windows at their measured distances from the corners.
Flatwalk turns your measurements, or a scan of each room's corners, into a flat you can furnish and walk through, free for one flat. It is launching on Google Play; join the waiting list at flatwalk.app.
Join the waiting list