Real Ruler - Accurate Measure
Actual-size on-screen ruler
Free · Designed for iPad. Not verified for macOS.
A ruler that is actually the right size. Calibrate once, measure in centimetres or inches, drop guide lines, and track coordinates. Works offline.
Real Ruler turns your screen into a ruler that measures at true physical size.
Most on-screen rulers are wrong because every device has a different pixel density. Real Ruler starts from a database of known devices and lets you calibrate against anything you already own, so a centimetre on screen is a real centimetre.
ACTUAL SIZE, NOT APPROXIMATE
Pick your device or calibrate by hand against a coin, a card, or a ruler you trust. Once it is set, it stays set.
MEASURE FROM ANY EDGE
Place a ruler along the left, right, top or bottom of the screen, or use more than one at a time, so you can line up whatever you are measuring the way that suits it.
GUIDE LINES
Drop a guide line anywhere and slide it into place to mark a measurement, compare two objects, or hold a reference while you work. Clear them in one tap.
TRACK COORDINATES
Turn on the crosshair to read exact positions as you move around the screen.
CENTIMETRES OR INCHES
Switch units instantly. Dark mode included.
NO ACCOUNT, NO INTERNET NEEDED
There is nothing to sign up for. The app does not read your contacts, photos or files, and measuring works entirely offline.
Real Ruler is supported by a single banner ad.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Refreshed App Store screenshots highlighting measurement units, screen calibration, and alignment guides.
The developer, Om Gawande, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Location
- Identifiers
- Usage Data
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Location
- Identifiers
- Usage Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Om Gawande
- Size
- 36.6 MB
- Category
- Utilities
- Compatibility
Requires iOS 16.4 or later.
- iPhone
Requires iOS 16.4 or later. - iPad
Requires iPadOS 16.4 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Contains
Advertising
- Copyright
- © 2026 Om Gawande