Here is a simple screen ruler application that allows you to accurately measure short lengths in cm or inches. This measuring tool (portrait orientation, Android 6 or newer) works on most tablets, phones and smartphones, regardless of their screen size or of their connection to the Internet. However, a bigger screen size offers higher resolution and better view of the divisions.

Features:

-- two units of measurement can be selected, cm and inches
-- FREE application - NO ADS, no limitations
-- measurement of the length on the two long sides of the device
-- this app keeps the phone's screen ON
-- easy measurements using 2 sliders with multi-touch capability
-- three measurement modes
-- fraction or decimal inches
-- simple calibration process
-- up, down, left or right text orientation