My friend Sana measured her living room with a phone, ordered a $900 sofa, and watched the delivery guys carry it back down the stairs. It fit the wall. It didn’t fit the door. A decent interior design app would have caught that, and I think most people open one for the wrong reason. They want a pretty render. What they need is a number. This guide covers what these apps actually do, which kind suits renters or people ripping out a kitchen, what the paid plans cost once you do the math, and three checks I’d run before buying any furniture. The short version: pick the app for the problem you have, and treat AI pictures as a mood, not a measurement.
What does an interior design app actually do?
Less than the screenshots suggest. Most of them draw walls, drop in furniture and show a 3D view. That’s the floor planner side. Planner 5D does it. So does RoomSketcher, and so does Sweet Home 3D, which is free and open source and looks like it was built in 2009. It works, though.
Then there’s the newer thing. You upload a photo of your room and an AI restyles it. Room AI is built around that, and Homestyler and Planner 5D have added their own versions. Houzz sits somewhere else, more marketplace than planner, with an AR view in its app. Pinterest and Canva are really moodboard tools, but plenty of people run their whole design process through them. Fine by me.
I haven’t used all of these, and I’d rather say so than pretend.
Which type of app fits you?
Renters first. You can’t move walls, so what you need is scale. Will this rug fit under the bed? Is that bookcase going to block the radiator? An AR preview or a basic free floor plan answers that. Planner 5D’s free plan is enough for a rough layout. Reviews say it locks about half the furniture catalog, though I couldn’t confirm that on the pricing page itself.
Owners doing a renovation need something else. Exact measurements, and an export you can show a contractor. Phone scans drift. Check every wall with a tape.
Can AI really redesign a photo of my room?
Sort of. You get a picture. Whether it’s your room is another matter. These tools generate images, they don’t measure anything, so a window can slide an inch, a wall can stretch, and a sofa can sit in a spot too narrow for it. Nobody notices until the delivery truck shows up. Use the output for color, style and mood. Take dimensions from the product page and your own tape. A pretty render of a sofa in a hallway tells you nothing about the hallway.
What do these apps really cost?
More than the free tier hints. Free plans tend to cap the catalog, add a watermark or ration the AI credits. Planner 5D is a decent example. From what I could find, Premium runs $19.99 a month or $59.99 a year, and Professional runs $49.99 a month or $399.99 a year. Those figures came from review sites quoting its pricing page, not the page itself, so check planner5d.com/pricing before you pay.
Weekly plans are the sneaky part. App Store listings love them. $2.99 a week sounds like pocket change. Times 52, it’s $155.48 a year. A $7.99 weekly plan lands near $415, which is real money for a room you could plan on a free tier.
My habit is boring. Free tier first, one room, one week. If I haven’t hit a wall by day seven, I’ll think about paying. Then I set a phone reminder the day before any trial ends. Apple and Google both list your active subscriptions in settings, and canceling takes about thirty seconds. Sana paid for a month she used for ten minutes.
What three checks stop the expensive mistakes?
Doorway first. Everybody measures the wall and forgets the way in. Measure the front door, the hallway turn, the stairs if there are any, and the narrowest spot between the street and the room. Sana’s sofa died at a door.
Second, walkways. Designers repeat a couple of rules of thumb and I think they hold up: about 30 to 36 inches for a main path through a room, and 14 to 18 inches between a sofa and its coffee table. Drag your furniture around in the app, then look at those gaps. Apps rarely warn you.
Third, tape. Painter’s tape on the floor, the exact footprint of whatever you’re buying. Live with it for a few days. Walk past it at night. It sounds silly, and it’s the only test that includes your actual habits. Then read the return policy before you pay, not after. Paint works the same way. Screens lie about color, so buy a sample pot and brush a patch on the wall.
Conclusion
The best interior design app is the boring one that matches your problem. Mine, if I’m honest, would be whichever lets me type in real dimensions. Sana’s second sofa is 78 inches wide. She measured the doorway twice and taped the outline on her floor for a week before ordering. Her cat slept in the rectangle the whole time. The new sofa came through the door in about a minute. It’s against the same wall. She sent me a photo, cat included, back on the sofa.
FAQs
Is there a free app to plan my room layout?
Yes. Sweet Home 3D is free and open source, and Planner 5D has a free plan with a limited catalog. Both work for a rough layout.
Are AI room design tools accurate?
They’re good for style and color and poor for measurements. The images can shift windows or stretch walls, so take real dimensions from the product page and a tape measure.
How much does Planner 5D cost?
Reviews from August 2026 list Premium at $19.99 monthly or $59.99 annually, and Professional at $49.99 monthly or $399.99 annually. Confirm on planner5d.com before you pay.
Do I need design experience to use a room planner?
No. Most let you drag furniture onto a plan or upload a photo. Start with one room and a free plan.