A measuring instrument is a device to measure a physical quantity.

In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world objects and events.

Established standard objects and events are used as units, and the process of measurement gives a number relating the item under study and the referenced unit of measurement.

Future Hi – Tech provide a range from simple objects such as rulers and stopwatches to electron microscopes and particle accelerators. Virtual instrumentation is widely used in the development of modern measuring instruments.