A metric is a measurable characteristic of a business activity. Metrics can quantify both physical characteristics (for example, the number or weight or volume of products made today) and less tangible characteristics (for example, customer satisfaction). Metrics can be used individually (for example, machine set-up time) and multiple metrics can be combined to make a single value (for example profit per employee). Management teams select and sometimes develop metrics to use as key performance indicators (KPIs) to help monitor, analyze and improve the processes in their business.

The metric system is a consistent set of units to measure physical quantities. It is based on meters (for length), kilograms (for mass), and seconds (for time).