Dimensions vs Measures Explained
Understanding the difference between dimensions and measures in Tableau
The Two Types of Fields
Every field in Tableau is either:
- Dimension (blue)
- Measure (green)
What are Dimensions?
Dimensions are categories that describe your data.
Examples:
- Product Name
- Customer Name
- City
- Date
- Category
Key Point: You group or filter by dimensions.
What are Measures?
Measures are numbers you want to analyze.
Examples:
- Sales
- Profit
- Quantity
- Temperature
- Score
Key Point: You calculate measures (sum, average, count).
Quick Comparison
| Dimension | Measure |
|---|---|
| Blue color | Green color |
| Categories | Numbers |
| Group by | Calculate |
| Text, dates | Numbers |
How Tableau Decides
Tableau automatically assigns:
- Text fields → Dimension
- Number fields → Measure
- Date fields → Dimension
Converting Between Types
Sometimes Tableau is wrong!
To convert:
- Right-click the field
- Select "Convert to Dimension" or "Convert to Measure"
Example: ID Numbers
Customer ID = 1001, 1002, 1003
Tableau sees numbers → Makes it a Measure
But IDs are categories, not for calculation!
Fix: Convert Customer ID to Dimension
Using Dimensions
Drag to:
- Columns - Categories on x-axis
- Rows - Categories on y-axis
- Color - Color by category
- Filter - Filter categories
Using Measures
Drag to:
- Columns/Rows - Creates axis with values
- Size - Bigger = higher value
- Color - Color gradient
- Label - Show values
Aggregation
Measures are always aggregated:
- SUM (default)
- AVG (average)
- COUNT
- MIN/MAX
To change: Right-click → Measure → Choose aggregation
Summary
Dimensions = Categories (blue) - for grouping Measures = Numbers (green) - for calculating
Know the difference for correct analysis!