To measure length using phone camera we just point camera towards the floor and start measuring length of any real world object. The length is measured based on special sensor available in phone, which can very accurately tell the distance between two coordinates in the real world.

Ruler App (ARCore) - free Augmented Reality measurement app for Android to tape measure the real world with your smartphone’s camera.

Ruler App (ARCore) app uses augmented reality technology (AR) to measure lengths in the real world with your smartphone’s camera. Simply target aim on the detected horizontal or vertical surface and start measuring!

Features:

Measure Distance - measure linear distance in cm

Measure Area and Volume- this feature is under development. will be updated on app soon.

Note:
Please note that AR Ruler requires an ARCore technology provided by Google. At the moment, ARCore is constantly improving, which, in turn, positively affects the quality of app. We do our best to make process of using ARCore technology for measurements more useful and pleasant

Accuracy:
The measurements obtained with the app are approximate, but fairly accurate in most everyday situations. Accuracy precision for the measured length is quite good. It gives pretty accurate measurements depending on user accuracy and competency. It's probably not 100% accurate, but it's always very close to the real measurement. Accuracy can be achieved within 1cm of range.

An incomplete list of other keywords intending to reach this app page: Ruler, AR, Measure length, Tape, measurement, ArRuler, ARMeasure, ArTape, Augmented Reality.
This is one of the most user friendly and accurate of all the AR Ruler apps you will find on the Play Store.

Note:
Please note that Ruler app requires ARCore library produced by Google. ARCore is constantly improving, which, in turn, positively affects the quality and accuracy of Ruler app.

Download the App Ruler app today to measure length in real world!

Functionality Improvement
UI Changes
Share measured scene
Bug Fixes