Calculated fields are custom expressions used to derive new values from existing data. Instead of storing these values in the database, calculated fields are computed at query time or within the BI tool.

Examples include:

• Profit = Revenue – Cost

• Conversion Rate = Conversions / Sessions

• Growth Rate = (Current – Previous) / Previous

• Customer Age = Today – Signup Date

Calculated fields allow analysts to create business logic without modifying source data. This flexibility is essential for exploratory analysis and rapid insight generation.

Calculated fields can exist at different layers:

• BI tool level (Tableau, Power BI, Looker)

• Semantic layer (centralized definitions)

• Data warehouse (SQL views or dbt models)

From a governance perspective, calculated fields should be standardized. When each analyst creates their own version of “conversion rate,” inconsistencies arise. Mature BI systems move critical calculated fields into the semantic layer or warehouse models.

Calculated fields can involve:

• Arithmetic operations

• Conditional logic (CASE statements)

• Time intelligence

• Aggregations

• Window functions

Performance matters. Complex calculated fields executed at query time can slow down dashboards. Precomputing them in the warehouse often improves speed.

Calculated fields bridge the gap between raw data and business logic, making them one of the most widely used features in BI tools.