The pupillary distance (PD) measurement is a requirement for people who want to purchase eyeglasses. Here, find out how to measure your PD using a mirror and a ruler.

It’s meant for measuring objects and that’s exactly what it does. When you need to measure something ‘in a pinch’, Ruler App is there. The makers of Ruler 2 are also having a contest - “In celebration ...

Instead, the tip of the ruler can be attached to the wall surface, etc., so if you want to use the ruler to 'measure the length and height of an object', the 'real ruler' is more suitable.