# How Will You Understand Dimensions and Measures?

Measures are numerical values that mathematical functions work on. For example, a sales revenue column is a measure because you can find out a total or average the data. Dimensions are qualitative and do not total a sum. For example, sales region, employee, location, or date are dimensions.

Dimensions affect the level of detail in the view. Measures contain numeric, quantitative values that you can measure. Measures can be aggregated. When you drag a measure into the view, Tableau applies an aggregation to that measure (by default).

Data fields are made from the columns in your data source. Each field is automatically assigned a data type (such as integer, string, date), and a role: Discrete Dimension or Continuous Measure (more common), or Continuous Dimension or Discrete Measure (less common).

• Dimensions contain qualitative values (such as names, dates, or geographical data). You can use dimensions to categorize, segment, and reveal the details in your data. Dimensions affect the level of detail in the view.

• Measures contain numeric, quantitative values that you can measure. Measures can be aggregated. When you drag a measure into the view, Tableau applies an aggregation to that measure (by default).

According to Tableau’s Knowledge Base, a dimension is a field that can be considered an independent variable. By default, Tableau treats any field containing qualitative, categorical information as a dimension. Generally, the measure is the number; the dimension is what you “slice and dice” the number by.