How to make a floor plan with your phone

The short version

A room scan works by walking the perimeter of a room with the phone held up, while the app captures the walls, doors and windows into a plan as it goes. On a LiDAR iPhone or iPad the scan runs on Apple’s RoomPlan; on Android it depends on the phone’s ARCore depth support. The result is a floor plan with wall lengths, openings and the overall footprint, produced in a few minutes and accurate to roughly the same standard as any other phone AR measurement: fine for planning, listings and quotes, not a substitute for a tape where a centimetre matters.

If your phone cannot run a room scan, you can still build a plan wall by wall with tap-to-measure. How to measure a room with your phone is that method.

Before you scan

• Light the room. Curtains open, lights on. A depth sensor copes better with dim rooms than a camera alone, but the camera is still doing the tracking, and tracking is what keeps the plan straight.
• Clear the perimeter. You need to be able to walk close to every wall. Move chairs and anything on the floor along the route; large furniture can stay.
• Open interior doors, close exterior ones. An open doorway reads as an opening, which is what you want. A door left half open sometimes reads as a short wall.
• Charge the phone. Scanning runs the camera, the depth sensor and the processor flat out. A phone that overheats will throttle and tracking quality drops with it.
• Wipe the lens. Always.

The walk

Start in a corner, or in a doorway if the room is small. Hold the phone upright at chest height, screen facing you, tilted slightly down so the camera sees where the walls meet the floor. Let the app initialise for a few seconds before moving.

Then walk the room slowly in one direction, keeping the phone up and the nearest wall in view. Slowly means slower than feels natural: a normal walking pace is too fast, and a fast turn at a corner is the most common way to lose tracking. At each corner, stop, turn the phone to look into the corner so both walls are captured meeting, and only then continue. Pause at each door and window and let the app see the whole frame, top to bottom.

Finish where you started, and overlap the beginning by a metre or so, so the app can close the loop and correct any drift that built up on the way round. Most scanners show the plan forming on screen as you go; if a wall is missing or looks bent, walk back along it slowly rather than starting again.

What a scan captures

A good room scan gives you the walls with their lengths, the openings — doors, windows and archways — with their widths and positions along the wall, the ceiling height, and the overall footprint of the room. Some scanners also identify large pieces of furniture and represent them as simple blocks. That is enough for a floor plan, a furniture layout, an area calculation and a rental listing.

What it does not capture

It helps to know the limits before you rely on the output.

• Furniture detail. A sofa is a box at best, and often left out. If you want furniture on the plan, measure it separately.
• Sloped ceilings and odd geometry. Scanners assume vertical walls and a flat ceiling. An attic room with a sloped ceiling, a curved bay or a bulkhead is captured approximately, if at all. Measure those features by hand and add them.
• Small fixtures. Radiators, sockets, light switches and skirting depth are not on the plan. If a kitchen fitter needs them, note their positions separately.
• What it could not see. A wall behind a wardrobe, a corner you turned too fast, a window hidden by a curtain. Gaps in the walk are gaps in the plan.
• Glass. A glass wall or a large mirror can confuse both the camera and the depth sensor. Expect to tidy those areas by hand.

Cleaning up

Look at the plan straight after the scan, while you are still in the room. Check that the corners are square where they should be, that the door and window positions match what you can see, and that no wall has a kink in it. Small irregularities in a wall are usually drift rather than a real bend; if you can edit the plan, straighten them. If a wall length looks wrong, measure it with tap-to-measure and compare. Name the rooms and the openings while it is fresh; a plan with “Bedroom 2, window to garden” on it is far more useful in a month than one without.

Check it against a tape

Pick the longest wall and one short one and measure both with a tape. If the scan agrees within a couple of centimetres on both, the plan is good for planning purposes. If it is out by more, or out by a consistent proportion on both, the scan was poorly initialised; rescan rather than adjust. How accurate is AR measurement explains why the proportional error matters.

Whatever the check says, a scanned plan is an estimate. Anything you are cutting, ordering to size or building to — worktops, fitted furniture, flooring cut to fit, anything structural — needs a physical measurement of that dimension before you commit.

Export and share

A plan that lives only on your phone screen is not much use to anyone else. Export it in a format the recipient can open: a PDF for a landlord, an estate agent or an insurer; an editable vector file if a designer or fitter wants to draw on it; a table of measurements if someone is pricing materials. TritonMeasure turns a room scan into a proof-pack PDF report or an editable SVG plan and CSV measurement table, and keeps the project on the device with no account required.

What people use it for

• Renting and letting. A plan with room dimensions in a listing answers the question every viewer asks. For tenants, a scan on move-in day is a record of the space as you found it.
• Renovation quotes. A builder or kitchen fitter can give a far better first quote from a plan with openings and ceiling height than from a phone call. They will measure again before they build, and they should.
• Furniture buying. Knowing the wall is 3.4 m with a radiator 60 cm from the corner settles whether the sofa fits before it is delivered.
• Insurance and records. Room areas and layouts for a contents policy, a claim, or simply a record of a property before work begins.
• Moving house. A plan of the new place before you have the keys full-time, so the furniture goes to the right room on the day.

Frequently asked questions

Can I make a floor plan with an iPhone?

Yes. On a LiDAR iPhone or iPad — the Pro models from the iPhone 12 Pro onwards and iPad Pro from 2020 — a room scan captures the whole room in one walk. On other iPhones you can build a plan wall by wall with tap-to-measure. See which iPhones and iPads have LiDAR.

How accurate is a phone room scan?

Comparable to other phone AR measurements: typically within a centimetre or two on a wall in good conditions, with error growing on long walls, in poor light and after fast turns. Check the longest wall against a tape, and use a physical measurement for anything you are ordering or building to.

Can I scan a room on Android?

It depends on the phone. Room scanning on Android relies on ARCore’s depth support, which is best on phones with a time-of-flight sensor and more limited on camera-only phones. Wall-by-wall tap-to-measure works on any ARCore-supported phone.

Does a room scan capture furniture?

At best as simple blocks, and often not at all. Treat a scan as walls, openings and ceiling height. If you want furniture on the plan, measure the pieces separately and add them.

Estimates, not certificates: every phone-based AR measurement is an estimate, TritonMeasure included. Verify anything safety-critical, structural or expensive with a physical tape or laser before you cut, order or sign.