Measure your room by walking it: AR scan on iPhone

In the iPhone and iPad app, point the camera at each corner of a room and tap. RoomSketch3D measures the walls and builds the outline. It uses ARKit camera tracking (no LiDAR needed) and captures one room per scan.

7 min readUpdated 2026-11-02

In the iPhone and iPad app you can measure a room with the camera instead of a tape measure. You stand in the room, point at each corner where the walls meet the floor, and tap Add Corner. RoomSketch3D measures the distances between the corners and turns them into a to-scale room outline you can then furnish.

Three things people often get wrong, so they're up front here. An AR scan measures one room at a time. It records the room's corners, not its doors, windows or furniture. It doesn't need LiDAR or Apple's RoomPlan. It uses ordinary ARKit camera tracking, so it works on iPhones without a LiDAR sensor and on ones where the sensor is broken. It's only in the iPhone and iPad app. The Android app and the web editor don't have AR, but they have other quick ways to start (see the end of this page).

How it measures. ARKit's world tracking follows the phone's position and tilt as you move, by combining the motion sensors with what the camera sees, and it finds flat surfaces such as the floor. When you tap Add Corner, the app casts a ray from the crosshair down to that floor and records the 3D point where it lands. The distance between two such points is a wall length. That's why the floor has to be visible and textured, why moving slowly helps, and why the result is a good first draft rather than a surveyor's measurement: check a wall or two with a tape and type the real lengths in, which takes a minute.

What you'll need

•The RoomSketch3D app on an iPhone or iPad running iOS 16 or later. A LiDAR sensor is not needed.
•A reasonably well-lit room where you can see the floor in each corner.
•A tape measure (or a laser measure) for checking one or two walls afterwards.

Step by step

1
On Home, tap AR Scan
In the iPhone or iPad app, go to Home (from the editor, tap the house button at the top left). Under Start a new floor plan, tap the AR Scan tile (Scan room with camera on wider screens). The tile only appears in the iOS app, on a device that supports AR: the web app and the Android app show the other five tiles (and the web adds From Backup).
AR Scan sits with the other ways to start a plan; it shows only in the iPhone and iPad app.
2
Name the design, then tap Start AR Scan
A short step opens with a Design Name box (it starts as My Home Design; type the room's name so you can find it later) and the reminder Point camera at the floor and tap each corner as you walk around. Tap Start AR Scan. The first time, iOS asks for camera access: allow it, or the scan can't start (you can turn it on later in Settings → RoomSketch3D → Camera).
Name the room first; the scan creates a design with this name.
3
Read the four-step card, then tap Got it!
The camera opens with a How to Scan Your Room card: (1) point your camera at a corner of the room, (2) the crosshair turns green when aimed at the floor, (3) tap Add Corner to mark the spot, (4) mark at least 3 corners, then tap Done. Its tip says to stand back, aim at visible corners and keep the camera steady. Tap Got it!, then move the phone around slowly for a second or two so it can find the floor. The status line reads Initializing AR... at first, then Point camera at the floor until it has found the floor, and Aim at a corner and tap 'Add Corner' once it's ready.

Aim at the first corner and tap Add Corner

Stand back a little and aim the AIM HERE crosshair at the spot on the floor where two walls meet. When the crosshair is green, tap Add Corner. If the crosshair isn't green you're not pointing at the floor yet. Tilt the phone down a little.

What the status line is telling you:

Message	What to do
Point camera at the floor	Tilt the phone down until the crosshair sits on the floor and turns green.
Slow down - moving too fast	Pause, then move more slowly.
Point at an area with more detail	The camera sees a blank surface (a plain wall, a glossy floor). Aim where the floor has some texture, or add light.
Move further from the last corner	You tapped twice on almost the same spot (less than 10 cm apart). Walk to the next corner.
Aim at the next corner (1/3 minimum)	Keep going: a room needs at least three corners.

5
Go round the room, corner by corner
Walk to the next corner in order, clockwise or anticlockwise, and add it the same way. As you go, the app shows Distance from last corner, a corner count, and a small live floor plan with the approximate perimeter and area (in feet or metres, following your measurement units). If you add a corner by mistake, tap Undo. Clear starts the room over (it asks first). For an L-shaped room, add each inside corner too: an L has six corners, a T or U shape eight.
The scan screen in the iPhone app: four corners placed, the live floor plan, Undo, Add Corner and Done.
6
Tap Done and tidy the outline
After the last corner, tap Done. Don't add the first corner again, because the outline closes on its own. Your design is created straight away and opens in the editor. Check one or two walls against a tape measure, because camera measurements are approximate: tap a wall on the plan, tap its length in the small bar beside it and type the length you measured (see Set an exact wall length). If the corners came out tangled, so the outline crosses itself (or the room came out too small to use), they open in the drawing editor instead: drag the stray corner into place and tap Create Floor Plan.
Tap a wall, then tap its length and type what your tape measure says.
7
Add the doors, windows and furniture
The scan gives you walls only. Add doors and windows from the Build panel and furniture from the catalog, the same as on a plan you drew by hand. See Add doors and Add windows.

Tips

Light and patience beat speed

AR tracking needs to see texture on the floor. Turn the lights on, move slowly, and give it a second at each corner. A plain, shiny or very dark floor is harder to track: Apple notes that pointing at a blank wall, or the lights going out, reduces tracking quality. While scanning, Slow down - moving too fast and Point at an area with more detail are the hints to watch. If a scan fails, the app says It's too dark to scan. Add more light and try again. or Lost tracking — move slowly and keep the room in view.: add light, slow down and start again.

Corners first, then check the long walls

Small errors add up around a room, so the long walls matter most. After the scan, measure the two longest walls with a tape and type those lengths in first, because they decide whether the sofa, bed or kitchen run fits.

Furniture in a corner?

Aim at the floor right beside the furniture, where the two walls would meet, and fix it afterwards by typing the wall lengths on the plan. You can also skip a hidden corner and add it later: split the wall and move the pieces, or drag the corner in Plan Settings → Layout → Outline Editor.

Whole home: scan the main room, then add the others

Use the scan for the room you care about most. Then add each neighbouring room to the same plan with Build → Add Room: tap the outside wall it sits against and set its size. Use interior walls to split a space. See Add a room beside an existing one.

Common mistakes

Trying to scan the whole house in one go

One AR scan gives one room outline. Walking from room to room in a single scan joins the corners into one odd shape. Scan one room, then build the rest with Add Room (or start from a floor-plan image, below).

Scanning each room as a new design

Each AR scan starts a new design, and separate designs can't be merged into one plan. To keep every room in one plan, scan once and add the other rooms inside that design.

Tapping the wall instead of the floor

Corners are measured on the floor. Aim where the walls meet the floor, not at the wall or the ceiling. A green crosshair means you're on the floor.

Frequently asked questions

Do I need an iPhone with LiDAR? Mine is broken or my phone doesn't have one.

No. The AR scan uses Apple's ARKit camera tracking (the floor detection every ARKit device has), not the LiDAR sensor and not Apple's RoomPlan. It works the same on iPhones and iPads without LiDAR, or with a broken LiDAR sensor, as long as the device runs iOS 16 or later (the app's minimum).

Can I scan more than one room?

One room per scan. To plan a whole floor, scan one room and add the others to the same plan with Build → Add Room, then split spaces with interior walls. You can also start from a photo or PDF of the floor plan. Each new scan creates a separate design, and designs can't be combined.

Does the scan pick up doors, windows or furniture?

No, only the room's corners. Add doors, windows and furniture in the editor afterwards. It takes a minute or two.

Is there AR scanning on Android or the web?

Not today. AR Scan is only in the iPhone and iPad app. On Android and on the web (app.roomsketch3d.com) use Rectangular Floor Plan (type the width and length), Custom Floor Plan (start from an L, T, U, alcove or round shape, or Draw Your Own), Floor Plan Image or PDF (trace a plan, or let AI draft it), or Use Room Photo (AI drafts a room from one photo). A plan you scan on iPhone opens on Android and the web when you're signed in to the same account.

How accurate is it?

Accurate enough to start, but treat it as approximate. Accuracy depends on light, the floor surface and how steadily you aim. Measure one or two walls with a tape, tap each wall on the plan and type its exact length. If the whole plan came out a little too big or small, Re-scale it from one measured wall (Plan Settings → Layout → Outline Editor → Re-scale): drag the two crosshairs onto two points you know the real distance between, type that distance, and nothing changes until you tap Update floor plan.

I don't see the AR Scan option. Why?

Check three things. You're in the iPhone or iPad app (not Android or a browser). You're on Home, looking under Start a new floor plan (from the editor, tap the house button at the top left). And the device supports ARKit with iOS 16 or later. If the tile still isn't there, update the app from the App Store. If the scan starts but says camera access is needed, turn it on in Settings → RoomSketch3D → Camera.

Does the scan work in metres?

Yes. The distance readout, perimeter and area on the scan screen follow your measurement units: feet and inches, or metres. Change them in Settings → Measurements & Defaults → Measurement Units before you scan; the plan itself can be shown in either afterwards.

What happens if a call comes in or I switch apps mid-scan?

The camera session pauses (the status reads Session interrupted, then Resuming...). ARKit tries to pick up where it left off if you come back to roughly the same spot and angle; if the corners look out of place afterwards, tap Clear and scan the room again.

Sources

Apple Developer: ARWorldTrackingConfiguration — World tracking follows the device in six degrees of freedom and finds horizontal surfaces; ray casting finds the real-world point under a screen position.
Apple Developer: Managing session life cycle and tracking quality — Why tracking needs light and visual detail (a blank wall or the lights going out reduce quality), and how a session relocalizes after an interruption.

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