18 Power BI Interview Questions With Sample Answers

Power BI interviews don’t just test whether you’ve used the tool.

They test:

• How well you understand data
• How you think about business questions
• Whether you can explain your work clearly

Below are 18 common Power BI interview questions, with simple, beginner-friendly sample answers you can confidently use or adapt.

1. What is Power BI?

Sample Answer:
Power BI is a business intelligence tool from Microsoft used to connect to data, transform it, create visualizations, and share interactive dashboards and reports.

2. What are the main components of Power BI?

Sample Answer:
Power BI Desktop for building reports, Power BI Service for sharing and collaboration, and Power BI Mobile for viewing dashboards on mobile devices.

3. What is the difference between a report and a dashboard in Power BI?

Sample Answer:
A report can have multiple pages and detailed visuals, while a dashboard is a single-page overview made from pinned visuals in the Power BI Service.

4. What is Power Query used for?

Sample Answer:
Power Query is used for data cleaning and transformation, such as removing duplicates, changing data types, merging tables, and filtering data before analysis.

5. What is DAX in Power BI?

Sample Answer:
DAX stands for Data Analysis Expressions. It is used to create calculated columns, measures, and custom metrics for deeper analysis.

6. What is the difference between a calculated column and a measure?

Sample Answer:
A calculated column is stored in the table and calculated row by row, while a measure is calculated dynamically based on filters and visuals.

7. What are relationships in Power BI?

Sample Answer:
Relationships define how tables are connected, usually through a key column, allowing Power BI to combine data correctly across tables.

8. What is a star schema and why is it recommended?

Sample Answer:
A star schema has one fact table connected to multiple dimension tables. It improves performance and makes data models easier to understand.

9. What are slicers in Power BI?

Sample Answer:
Slicers are interactive filters that allow users to filter visuals by selecting values like dates, regions, or product categories.

10. How do you handle large datasets in Power BI?

Sample Answer:
By using proper data modeling, removing unnecessary columns, using measures instead of calculated columns, and applying filters early in Power Query.

11. What is the difference between Import and DirectQuery?

Sample Answer:
Import loads data into Power BI for faster performance, while DirectQuery queries the data source in real time but may be slower.

12. What is row-level security (RLS)?

Sample Answer:
Row-level security restricts data access so users only see the rows they are allowed to see, based on defined roles and filters.

13. How do you refresh data in Power BI?

Sample Answer:
Data can be refreshed manually in Power BI Desktop or scheduled automatically in the Power BI Service.

14. What causes incorrect numbers in Power BI reports?

Sample Answer:
Common causes include incorrect relationships, wrong join types, duplicate data, incorrect filters, or poorly written DAX formulas.

15. How do you optimize Power BI report performance?

Sample Answer:
By reducing data size, simplifying visuals, optimizing DAX, using star schema models, and avoiding unnecessary calculations.

16. What is the difference between SUM and SUMX?

Sample Answer:
SUM adds a column directly, while SUMX evaluates an expression row by row before summing the results.

17. How do you explain Power BI insights to non-technical users?

Sample Answer:
By focusing on business impact, using simple visuals, avoiding technical terms, and explaining what changed, why it matters, and what actions to take.

18. Why do companies use Power BI instead of Excel?

Sample Answer:
Power BI handles larger datasets, supports interactive dashboards, automates refreshes, and enables easy sharing across teams.

Don’t memorize answers word for word.

Understand:

• Why the feature exists
• When to use it
• How it solves business problems

That’s what interviewers care about most.

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