
1. Adornably

2. HomeSnap

4. myPANTONE

5. Paint Tester

6. Mark on Call

7. Easy Measure

11. I.D. Wood

13. Home Sizer

14. Chairish

15. BrightNest

16. iHandy Level

17. Houzz

OMG, SHAZAM FOR PAINT COLORS IS REAL.
This app takes the guesswork out of buying new furniture; you're able to take a picture of your space and actually see how new pieces would look within it. Furnish does the same thing, with different retailers like IKEA and West Elm.
Satisfy your voyeuristic urges — this app will tell you how much a house costs when you take a picture. Creepazoid.
It's basically Shazam for paint colors (although restricted to Benjamin Moore brand paints, clearly).
This works in much the same way as the Benjamin Moore app, and allows you to create complementing palettes in every shade imaginable.
So you can see how a given color will look in a room before you take the plunge.
This app does everything from helping you develop floor plans through the conclusion of your project. It's basically like having an on-call interior designer in your pocket*.
*But he can breathe and stuff.
You'll never need to throw a clunky tape measurer in your bag again.
Or just measure the whole darn room at the same time.
This app helps you visualize your space in three dimensions, and it's available for free in addition to its paid upgrade packages. It's basically The Sims IRL.
Determine exactly how much paint (and/or $$$) you'll need to paint any kind of project.
This app operates like a visual dictionary for types of wood, and identifies the properties of each (for example, which kinds make great cabinets vs. beams).
It'll map all the treasure troves/junk piles in a thirty-mile radius.
If you're building a house from the ground up, this handy app helps you calculate square footage and costs as well as save notes about the function of each room.
Buy and sell vintage furniture on the go.
Whether you're making over your home or just going about the day-to-day business of living in it, BrightNest provides helpful step-by-step guides and DIY tips for everything from painting a room to unclogging a toilet.
No more crooked picture frames.
Like Pinterest, Wikipedia, and Craigslist for home design all rolled into one. Even if you're not ~actually~ working on a real project at the moment, this app is so addictive that you'll want to pretend you are.