# Ruler Professional > iOS device measurement tool for length in metric and imperial units. (iPhone/iPad app by KBIC International Ltd.) - Source: https://appshunter.io/ios/app/ruler-professional/id527471088 (this page in markdown: same URL + `.md`) - Developer: [KBIC International Ltd](https://appshunter.io/developer/505094094) - Category: Utilities, Productivity - Price: Free with in-app purchases - Rating: 3.30/5 from 3 App Store ratings · 14 written reviews indexed - Age rating: 4+ - Requires: iOS 10.0 · 7 MB - Languages: American English, French (France), Japanese, Chinese (Simplified, China), Chinese (Traditional, Taiwan) - Released: 2012-05-24 - Data updated: 2026-06-02 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/ruler-professional/id527471088/reviews.md ## What is Ruler Professional? Turn your iPod Touch, iPhone or iPad into a ruler! You want to measure in centimeters? or inches? We support both the metric and English systems. You want to measure the length of an object? You can move the two red lines in the app and the distance between the two lines will be displayed to you immediately! ## Key features - Device as a ruler - Metric and imperial units - Adjustable measurement markers - Real-time distance display ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Ad Removal | $0.99 | one-time | ## Recent user reviews (10 of 14) All indexed reviews: https://appshunter.io/ios/app/ruler-professional/id527471088/reviews.md ### 1/5 — Grossly inaccurate *2020-02-16* It’s not even funny how horribly inaccurate that this ruler is on my iPhone XR. ### 4/5 — Recalibrate and get the 5th Star!! *2019-02-19, version 1.9* I also found that on iPhone 7P the ruler pro app measures 1” as 1,1/8”. Is there a way to recalibrate for correction? Otherwise I like the ruler with adjustable redlined so that you can use it like callipers and set small items right on the screen between redlines for accuracy & precision. ### 4/5 — In case you’re wondering... *2017-10-26* There are no instructions, so finding out how to switch from inches to centimeters may be difficult. The i with a circle around it is the key. But it’s so close to the ad at the bottom of the screen, it took me a bit to realize it’s not a link to give me more information about the ad. The ruler is nice and simple other than that. It’d definitely be nice to have a simple tutorial opening page to explain the options available. The red lines need an explanation (though they can be self-explanatory). Not everything is obvious to everyone. ### 1/5 — I got the app but didnt go on it *2017-06-04, version 1.8* I am lazy so bye ### 1/5 — Waaaaay off *2015-03-13* Downloaded to an iPad mini and the scale is ridiculously off. ### 1/5 — Inaccurate measurements for 6 plus *2015-03-05, version 1.7* One inch is actually about 1 1/8 inch on the iPhone 6 plus. I could not find a way to calibrate the app. ### 5/5 — iPad retina *2014-08-05* Just downloaded this and checked the calibration against my ruler. It's spot on. Measures in inches and centimetres and their increments. 5⭐️! ### 5/5 — Easy to use *2013-07-13* Simple, clean design, and easy to use ### 2/5 — Not retina *2013-03-22, version 1.3* Text and lines are fuzzy. ### 5/5 — It's a ruler *2013-01-15, version 1.3* It works. It's a ruler. ## Frequently asked questions about Ruler Professional ### What units does Ruler Professional support? Ruler Professional supports both metric (centimeters) and English (inches) systems for your measurement needs. ### How do I measure an object's length with Ruler Professional? You can measure an object's length by moving the two red lines within the app. The distance between these lines will be displayed to you immediately. ### What devices is Ruler Professional compatible with? Ruler Professional is designed for iPhone, iPad, and iPod Touch devices. ### What is the age rating for Ruler Professional? Ruler Professional has an age rating of 4+, making it suitable for a wide range of users. ### When was Ruler Professional last updated? The latest version of Ruler Professional was released on August 15, 2017. ### Does Ruler Professional have ads? No, Ruler Professional does not contain advertisements. ### What is the user rating for Ruler Professional? Ruler Professional has an average rating of 3.3 stars based on 3 user ratings. ## Version history (last 5 releases) ### 1.9 — 2017-08-15 This app has been updated by Apple to display the Apple Watch app icon. Bug Fixes ### 1.8 — 2016-10-05 iPad Pro and iPad Mini are now supported Bug fixes ### 1.7 — 2014-10-16 App updated for iPhone 6 and iPhone 6 Plus ### 1.6 — 2014-03-24 AdMob SDK Update ### 1.5 — 2013-11-25 Optimized for iOS 7 Optimized for iPad Mini with Retina display ## Apps similar to Ruler Professional | App | Rating | Price | Category | | --- | --- | --- | --- | | [Life-Size Ruler](https://appshunter.io/ios/app/life-size-ruler/id6503698542) | 3.5 (2) | Free | Utilities | | [BoviShow](https://appshunter.io/ios/app/bovishow/id1621261775) | — | Free | Utilities | | [Pocket,Ruler](https://appshunter.io/ios/app/pocketruler/id6741355487) | — | Free | Utilities | | [Quick Measure - Precise Ruler](https://appshunter.io/ios/app/quick-measure-precise-ruler/id6738601525) | 5.0 (4) | Free | Utilities | | [星苗國際教育體系](https://appshunter.io/ios/app/id1426348511) | — | Free | Utilities | | [臺北市預約公車](https://appshunter.io/ios/app/id1494075669) | — | Free | Utilities | ## More apps by KBIC International Ltd - [Music Factory -](https://appshunter.io/ios/app/music-factory/id509978677) - [Music Factory Lite -](https://appshunter.io/ios/app/music-factory-lite/id510346984) - [Vocal Remover](https://appshunter.io/ios/app/vocal-remover/id518520239) - [Vocal Remover Lite](https://appshunter.io/ios/app/vocal-remover-lite/id518520396) - [Pitch Changer](https://appshunter.io/ios/app/pitch-changer/id518521577) - [Pitch Changer Lite](https://appshunter.io/ios/app/pitch-changer-lite/id518521836) All apps by KBIC International Ltd: https://appshunter.io/developer/505094094 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-02.*