Have you ever toured a house you really liked, but can’t quite remember some aspects of the home’s layout? Or perhaps you just purchased a home and want to keep a copy of the floorplan in your pocket—a handy reference tool when shopping for furniture or for giving friends and relatives a remote tour of your new home.

Today’s smartphone technology makes it possible! However, before taking any photographs that document the interior of someone else’s home, remember that you need to get permission from the owner first. Ask your buyer’s agent about this.

Here are four options to explore:

1. MagicPlan

This floorplan tool is a “freemium” software tool (a free version, with optional higher-end paid features) available for iPhone and Android users. It “auto-magically” creates a 2D and 3D version of any room with a few simple taps.

Here’s how it works:

Stand in the center of the room and move the camera from one corner to the next, tapping the screen to identify each corner of the room. Rooms can be any shape. Just find all the corners.

After replicating a model of the room, including approximate measurements, you can add furniture, customize wall and flooring finishes, and add other decorative touches. When finished, you can take a 3D tour of your creation!

MagicPlan is commonly used to plan DIY projects, to furnish your home, and to generate job estimates.

It’s free for personal use on your phone or tablet, but not all options are available on the free version, including saving your designs in multiple file formats. As of this writing, Android users can pay $2.99 for each downloaded plan or $9.99/month for a standard subscription. For iPhone users, the fees are $3.99/plan or $13.99/month.

There is a charge of $2.99 for each downloaded plan or $9.99 per month for a standard subscription on Android, $3.99 for each downloaded plan or $13.99 per month on Apple.

2. RoomScan

Only available for iPhone, RoomScan offers three ways to generate a 2D or 3D floorplan: 1) hold your phone against each wall; 2) use your phone’s camera for augmented reality scanning; or 3) draw manually, using an integrated laser measuring tool.

If you need to generate more precise measurements or want to stitch together multiple rooms into a unified floorplan, you’ll need to upgrade to the Pro version ($5.99). The Pro version also includes options to scan building exteriors, yards, and gardens.

Download RoomScan in the iTunes app store.

3. Planner 5D

This free tool lets you create 2D and 3D versions of existing spaces—or create one of your own—using your smartphone, tablet, or laptop.  It does not estimate room measurements but does offer “design inspiration” in the form of graphics from other designers.

Once complete, you can use VR glasses to “tour” your creation in virtual reality.

The app is free and includes a modest catalog of items to occupy the spaces you create. Unlocking all the options, including HD “photorealistic” rendering of finished layouts, requires in-app purchases.

Planner 5D is available for Mac, iPhone, Android, Win10, and on the Amazon App Store.

4. CamToPlan App

CamToPlan is a flat, 2D measurement tool that quickly creates basic floorplans. It’s available on the Google Play Store and on iTunes. The app is free, but there’s also a “Pro” version ($3.99 for Android and $4.99 for Apple).