Ruler is an accurate length measuring tool. By measuring the size of your monitor, you create one or more screen rulers on the screen that are the same as a real ruler, so that you can measure length without having a real ruler.

List of adaptive devices:
- iPhone 4,
- iPhone 4S,
- iPhone 5,
- iPhone 5c,
- iPhone 5s,
- iPhone SE,
- iPhone 6,
- iPhone 6 Plus,
- iPhone 6s,
- iPhone 6s Plus,
- iPhone 7,
- iPhone 7 Plus,
- iPhone 8,
- iPhone 8 Plus,
- iPhone X,
- iPhone XR,
- iPhone XS,
- iPhone XS Max,
- iPhone 11,
- iPhone 11 Pro,
- iPhone 11 Pro Max,
- iPad 1,
- iPad 2,
- iPad (3rd generation),
- iPad (4th generation),
- iPad mini 1,
- iPad mini 2,
- iPad mini 3,
- iPad mini 4,
- iPad mini (5th generation),
- iPad Air 1,
- iPad Air 2,
- iPad Air (3rd generation),
- iPad Pro (9.7-inch),
- iPad Pro (10.5-inch),
- iPad Pro (12.9-inch),
- iPad Pro (12.9-inch) (2nd generation),
- iPad Pro (11-inch),
- iPad Pro (12.9-inch) (3rd generation),
- iPad (5th generation),
- iPad (6th generation).

What’s New

Version 20.6.1

- Adaptive iPad Pro (12.9-inch) (4th generation);
- Adaptive iPad Pro (11-inch) (2nd generation).

Ratings and Reviews

3.9 out of 5
16 Ratings

16 Ratings

mKohler6 ,

No-Ad Option

This is a fairly simplistic ruler app that suits the needs I have, however, the ads are kind of annoying. This is an app I would pay a reasonable price around (maybe) $0.99 to make the ads go away forever. Otherwise, great app!

Hydrozoline ,

Ruler is in centimeters, not inches

The app asks you for your screen size (there are 3 choices), then it shows you a ruler on two sides of your screen. Tapping on the screen gives you a crosshair sort of thing that you can move around. Unfortunately, the rulers aren't in inches (even though the 3 screen size choices are), and landscape orientation isn't supported. I also wish it would automatically figure out my screen size. Still, I like the crosshair so I'll keep the app (unless I find something better).

The one reviewing ,

So amazing

I couldn’t find a ruler around the house and was thinking of getting another ruler from the local target and then found this app. Made my own ruler from this app. Recommended for sure!!!


Kun Mao
21.8 MB

Requires iOS 9.0 or later. Compatible with iPhone, iPad, and iPod touch.


English, Chinese, Simplified Chinese, Traditional Chinese

Age Rating
In-App Purchases
  1. No Ads $0.99
  2. Tip $0.99


  • Family Sharing

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

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