About Ruler
Use a coin or a credit card to calibrate the ruler anywhere, when you don't have a real ruler with you! - Ad free, for real, forever! - Pick your units: fractional inches, decimal inches, centimeters or millimeters - Calibrate your ruler with a credit card to get you started anytime, anywhere - Don't have a credit card with you? Calibrate your ruler with a coin! - Calibrate your ruler with a real ruler to achieve the best precision in your measurement transfers - Manually set the ruler to a known length for accurate measurements - Night mode to save battery (on AMOLED screens) and to relieve your eyes at night - Save your measurements for future use - No permissions required
All Ruler APK versions
No versions available.
Frequently Asked Questions
Yes. Every Ruler APK on APK.now is automatically scanned and the cryptographic signature is verified against the original publisher's certificate (Xalpha Lab). Files that fail verification are removed before they ever reach the catalog.
Enable 'Install from unknown sources' for your browser (or the file manager you use to open the APK) under Settings → Apps → Special access. Tap the downloaded Ruler APK, confirm the prompts, and Android installs it just like any app from the Play Store.
The latest Ruler version available on APK.now is the latest version. We track new releases from Xalpha Lab continuously and add them to the catalog as soon as they pass verification.
Yes — every Ruler APK and every version on APK.now is free to download. We never gate downloads behind sign-up, surveys, or paywalls.
APK.now keeps a full archive of every Ruler release, including older versions that the Play Store has already replaced. The APKs work on devices without Google Play Services (Huawei, GrapheneOS, Amazon Fire) and are signature-verified so you can be confident the file is genuine.