Measure anything your iPhone or iPad can take a picture of!

★★★ 40% off! Celebrating RulerPhone's success with a sale! ★★★

RulerPhone has now been downloaded by *many hundreds of thousands* of iPhone, iPad, and iPod users!

“ of the coolest apps I have seen so far.”

“...the best ruler app for the iPhone.”
- iPhoneCave

“ of the few apps that I keep on my personal iPhone.”
- Bryan,

“...unique app, accurate measurements.”
- iPhoneAppPodcast

“RulerPhone will inevitably come in handy, so you might as well buy it now!”
- got apps?

RulerPhone turns your iPhone and its camera into a true measuring tape -- all you need is something already in your wallet: a gift card, MetroCard, driver's license, or credit card.

Buy RulerPhone - the widely acclaimed, "best ruler app for the iPhone" - now for only $3.99.

New Version! RulerPhone can now also measure the distance from your iPhone's camera to any object and save any measurements to your photo library!

RulerPhone is not like other apps: it does not just display an image of a ruler on your iPhone, and it does not use GPS to calculate distance. RulerPhone can accurately measure distances ranging from a few inches to 10 feet and beyond.

What others are saying:

" of the best applications for the iPhone."
"I was surprised how well this worked...I would buy this for $10."
"Works like a charm...super easy to use."

How does it work?

Place any credit-card sized card next to the object you'd like to measure, snap a picture with your iPhone's camera, align your image with the card placeholder that RulerPhone displays on-screen, and you are ready to measure anything in your picture just by dragging your finger. You can also use any picture already stored in your iPhone or iPod Touch photo library.

RulerPhone figures out the dimensions you're measuring using the card in your picture as reference. Once you've aligned the card in your image with the on-screen card placeholder, you simply drag your finger across the screen to measure distance. RulerPhone will display a ruler over your picture that you can drag and adjust to fine-tune your measurements (as seen in the screenshot below).

Is it accurate?

RulerPhone is accurate within half an inch when measuring distances of three feet or less and can be accurate within a single inch when measuring distances up to 10 feet as long as the instructions are followed closely. Much of RulerPhone's accuracy depends on the user's ability to follow the on-screen instructions and tips for accuracy. Once these steps are mastered, RulerPhone is a very accurate tool. RulerPhone's accuracy will also continue to increase as the iPhone's camera is upgraded.

When does it not work?

RulerPhone does not measure depth in a photograph. When you take a picture, RulerPhone can only measure an object's height and/or width. Similarly, if you take a picture with your MetroCard or driver's license off at an angle instead of pointing directly at the camera, RulerPhone's accuracy will be compromised. All of this information is in RulerPhone's instructions and accuracy tips that are available once you buy the app, and more information is found at the website below.

How can I learn more?

Go to to learn more, get tips, and watch video of RulerPhone in action.

What's New

Version 4.52

* Quite a few crash fixes -- sorry to those who've run into trouble!

Recent updates:

* Support for iPhone 5's juicy new screen.

* Fix screenshot quality when saving measurements on retina display.

* Crash fixes

Customer Reviews

1.7 out of 5

6 Ratings

6 Ratings

Ineffective at best


I (foolishly) assumed the app would use the photo's focal length and determine measurements by triangulation. I was incorrect. Additionally, the app doesn't incorporate edge distortion (inherent to any fixed lens) so accuracy is lost exponentially as the measurement calipers approach the edge of your photo. A $3.99 app should be of a substantially higher caliber. Check the emailed receipt from iTunes to have your money refunded.

Good pocket tape measure

Towa Apple

I sure do like this digital tape measure app I compare it to a real tape measure and the measurements are about the same which is nice and not off balance.

Does Not Work


Cannot get it to measure correctly. It used to work, so fix the bugs or refund my money.


Ben Kamens
8.6 MB
Requires iOS 4.3 or later. Compatible with iPhone, iPad, and iPod touch.
English, Dutch, French, German, Simplified Chinese, Spanish, Traditional Chinese
Age Rating
Rated 4+
© 2010 Ben Kamens


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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