Measure allows you to measure the distance from you and the height of an object.
Just set the distance of the center of the phone from the ground and aim the base of the target to get the distance.
All measure units are in centimeters.
For short range measure, the accuracy should be about 5-10cm, so keep in mind to not take the value as a precise measure.
Yes, there are a lot of apps that do exactly what this app do but they arent free.