Really handy!
Super easy to use. Comes in handy when I need to measure something real quick!
Free
In-App PurchasesWith Ads
About
This app provides a highly accurate, actual-size ruler that adapts to any screen. It offers dual-edge measurement, a precision caliper mode, and universal calibration for reliable real-world measurements. It functions offline and is designed for various devices.
✓Actual-size accuracy on any screen
✓Dual-edge metric and imperial scales
✓Precision caliper mode for thickness
✓Universal card calibration
✓High-contrast dark and light themes
✓100% offline and private
Show original description
What's New in Ruler
1.0.6
October 24, 2026
Added support for iPhone Duo.
1
Subscriptions & In-App Purchases
$1.99
Remove Ads & Unlock Full Ruler
Remove ads & unlock full-length ruler.
User reviews
Developer apps
FAQ
How does Ruler ensure actual-size accuracy on different devices?
Ruler uses an intelligent hardware display adaptation engine that maps your device's native dots-per-inch (DPI) to guarantee 1:1 actual-size fidelity. This ensures that 1 centimeter on your screen is precisely 1 centimeter in the physical world, regardless of screen size or aspect ratio.
Can Ruler measure in both centimeters and inches simultaneously?
Yes, Ruler features dual-edge simultaneous measurement. The left edge displays the metric scale (cm & mm), while the right edge shows the Imperial scale (inches with 1/16" graduations), both visible at the same time.
What is the precision caliper mode in Ruler?
The precision caliper mode allows you to activate dual adjustable caliper jaws by pinching. It displays live dimension arrows and real-time thickness readouts, making it ideal for measuring small objects like coins, screws, or jewelry with high accuracy.
How do I calibrate Ruler for my device?
Ruler offers Universal Card Calibration, allowing you to verify or fine-tune your device's accuracy using any standard credit, debit, or ID card (ISO ID-1 standard 53.98 mm). This ensures precise measurements anywhere in the world.
Does Ruler work offline?
Yes, Ruler is 100% offline and private. No internet connection is required, and there is no background tracking or sign-in needed, ensuring your measuring tool is always ready when you are.
What themes are available in Ruler?
Ruler offers high-contrast dark and light themes. You can switch between a glare-free OLED dark mode and an ultra-sharp, high-contrast black-on-white theme designed for optimal visibility, even outdoors.
Is Ruler suitable for all screen sizes?
Yes, Ruler is engineered to universally adapt to any screen size and aspect ratio, from compact phones to large-screen devices and iPad tablets. Its adaptive precision engine ensures accurate measurements across all supported devices.
Does Ruler have ads?
Yes, Ruler contains advertisements. As a free application with in-app purchases, advertisements are displayed to support its development and availability.
