Ruler - CM, MM, Inches

Ruler - CM, MM, Inches

CM, MM, In. Measure Anything.

79 ratings
60 reviews
Free
In-App PurchasesWith Ads

Details

  • Released
  • Updated
  • August 12, 2015
  • August 22, 2026
Ruler - CM, MM, Inches screenshot #1 for iPhone
Ruler - CM, MM, Inches screenshot #2 for iPhone
Ruler - CM, MM, Inches screenshot #3 for iPhone
iphone
ipad
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About

Measure lengths, widths, and diagonals accurately using your phone. Switch between metric and imperial units, and utilize flexible starting points for precise measurements in any direction. Features auto-calibration for minimal error and a screen lock to preserve readings.

Multi-mode measurement (CM, MM, Inches, Fractions)
Flexible starting points
Full-direction measurement (horizontal, vertical, diagonal)
Auto-calibration for accuracy
Screen lock for preserving readings
Ad-free VIP option
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What users say

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What's New in Ruler

26.1

August 22, 2026

New UI designed for iOS 26.

Subscription plans

VIP

Ad-free | auto-renews, cancel anytime

$4.991 Month
3 Days trial
How to cancel Ruler subscription ⁉️
3

In-App Purchases

$4.99

Sponsor

Thank you for your sponsorship.

User reviews

Too much ads

This app is pretty basic — nothing special or groundbreaking — but it’s completely ruined by the excessive ads. You get bombarded with them from start. It feels way too greedy for what it offers.

Too many ads

Ads keep popping up, even can’t use it.

Ads block the ruler lol

They literally put ads over the measurements, like, it’s a ruler app that hides the ruler to advertise to you. Hilariously bad.

Simple and easy

This is a very simple, flexible, and easy to use ruler app. No frills, just ruler. I like that you can have just cm or just inches or you can have both. Only thing I’d change is that when they have both it doesn’t line up at zero. Otherwise it would be 5 stars. Under the settings there’s a way to remove the ads in kid mode.
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Beautiful simple app, Screaming loud ads

Second time I opened the app I received an ad at the very top volume that my I pad could play. Nearly dropped it out of shock. No way to pay for a version without ads. It's a shame, as it is really nice. Deleting after 20 min.

Developer apps

User experience

🐞

Reported Bugs

9 issues

Ads pop up constantly, making app unusable

Bug

Ads overlay the ruler/measurements

Bug

App crashes constantly

Bug

Black screen issue

Bug

Inaccurate measurements (especially inches)

Bug

Paid no-ad version no longer works

Bug

Calibration issues on specific devices

Bug

Numbers are upside down

Bug

Doesn't work with 10.5" iPad

Bug

Requested Features

12 requests

Option to remove ads via one-time purchase

Feature

Ability to calibrate the ruler

Feature

Offset crosshairs to see numbers

Feature

Fractional inch (1/8, 1/16) display option

Feature

Option to hide ruler digits

Feature

Support for larger screen sizes (e.g., 10.5" iPad)

Feature

Ability to scroll and see more than screen size

Feature

Automatic screen size detection

Feature

Landscape orientation support

Feature

Add more measurement tools (plumb bob, seismometer, etc.)

Feature

Option to hide calculator and other unwanted features

Feature

Add click on every 1/10 of an inch in setup

Feature

FAQ

What can this app measure?

This app allows you to measure lengths, widths, and diagonals of objects or spaces directly using your phone's screen. It supports various units, including centimeters, millimeters, inches, and fractions of inches, making it versatile for different needs.

How accurate is the measurement?

The app features auto-calibration technology that dynamically adjusts based on your device model to ensure a low error rate, typically ≤1%. You can also use the screen lock feature to freeze measurements and prevent accidental slips or touches, further enhancing precision.

Is this app free to use?

The app is free to download and use, offering core measurement functionalities. However, it also provides an optional VIP subscription for an ad-free experience, which is auto-renewable and priced per month. Details on subscription costs are available within the app.

What devices is this app compatible with?

This app is designed for mobile devices and is available for download, implying compatibility with smartphones and tablets. The auto-calibration feature specifically adjusts based on the device model to optimize accuracy.

How can I switch between measurement units?

You can freely switch between metric units (cm/mm) and imperial units (inch/fractions) within the app. It also offers a dual-unit display option, allowing for instant comparison between different measurement systems.