A Complete Power BI Interview Preparation Guide for Freshers & Experienced
Power BI continues to dominate the Business Intelligence and data analytics landscape in 2025 and is projected to grow even bigger in 2026. With companies adopting data-driven decision-making at a rapid pace, the demand for skilled Power BI Developers, Power BI Analysts, Data Analysts, and Business Intelligence Engineers has surged.
If you are preparing for a Power BI Interview in 2025–2026, you need updated, practical, scenario-based interview questions. This article covers the Top 30 Most Asked Power BI Interview Questions and Answers, along with explanations suitable for both freshers and experienced candidates.
Let’s begin!
⭐ Why Prepare for Power BI Interviews? (2025–2026)
Microsoft is consistently adding new features, making Power BI a leading BI tool worldwide. According to market trends:
- Power BI adoption will grow 25% YoY between 2025–2026
- Demand for Power BI professionals is highest in IT, Banking, Retail, Healthcare, SaaS, and Consulting
- Average salary for Power BI professionals in 2026 is expected to increase by 30%
This makes it essential to master the most commonly asked Power BI interview questions for 2025 & 2026.
Top 30 Most Asked Power BI Interview Questions and Answers (2025 & 2026)
Power BI Interview Questions and Answers for Freshers
1. What is Power BI?
Answer:
Power BI is a cloud-based Business Intelligence and data visualization tool developed by Microsoft. It allows users to connect to multiple data sources, clean data, create reports, build interactive dashboards, and share insights in real time.
Key features:
- Drag-and-drop interface
- DAX calculations
- Data modeling
- Real-time dashboard updates
- Cloud collaboration via Power BI Service
2. What are the main components of Power BI?
Answer:
Power BI consists of:
- Power BI Desktop – Used for data modeling & report creation
- Power BI Service – Cloud platform to publish and share reports
- Power BI Mobile Apps – View reports on Android/iOS
- Power BI Gateway – Connect on-premise data to cloud
- Power BI Report Server – On-premise report hosting
- Power BI Embedded – Embed dashboards into applications
3. What is DAX in Power BI?
Answer:
DAX stands for Data Analysis Expressions.
It is a formula language used to create calculated columns, measures, and custom calculations.
Examples:
SUM(Sales[Amount])
CALCULATE(SUM(Sales[Amount]), Sales[Region] = "India")4. What are Filters in Power BI?
Answer:
Filters help restrict the data shown in a report.
Types of filters:
- Visual-level filter
- Page-level filter
- Report-level filter
- Drillthrough filter
- Cross-filter
- Slicer (visual filter)
5. What is a Slicer in Power BI?
Answer:
A slicer is a visual element that lets users filter data interactively.
Common slicers include date slicers, category slicers, and numeric range slicers.
6. What is Power Query?
Answer:
Power Query is a data transformation tool used to clean, reshape, and combine data.
It follows M Language, which is case-sensitive.
7. What is Query Folding?
Answer:
Query folding is the process where Power Query pushes data transformations back to the source database to improve performance.
8. What are the different types of Refresh in Power BI?
Answer:
- Manual Refresh – Triggered by user
- Scheduled Refresh – Automated
- Real-Time Refresh – Streaming datasets
- DirectQuery Refresh – On-demand from source
9. What is the difference between DirectQuery and Import Mode?
Import Mode
- Data is imported into Power BI
- Highest performance
- Ideal for small to medium datasets
DirectQuery
- No data stored in Power BI
- Queries sent to source in real time
- Ideal for large datasets
10. What are Measures in Power BI?
Answer:
A measure is a dynamic calculation evaluated at query time.
Example:
Total Sales = SUM(Sales[Amount])Power BI Interview Questions for Experienced Candidates (Advanced)
11. What is Row-Level Security (RLS)?
Answer:
RLS restricts data access for specific users based on roles.
Example scenario:
- Regional managers only see data for their region
- RLS filters applied using DAX expressions
12. What are Power BI Dataflows?
Answer:
Dataflows allow cloud-based ETL using Power Query Online.
They store transformed data in Azure Data Lake and can be reused across reports.
13. Explain Star Schema and Why It Is Used in Power BI.
Answer:
A Star Schema consists of a central fact table surrounded by dimension tables.
Benefits:
- Better reporting performance
- Faster DAX calculations
- Clean data modeling
- Avoids complex joins
14. What are Composite Models?
Answer:
Composite Models allow combining DirectQuery, Import, and Dual Storage modes in one dataset.
15. What is the Difference Between Calculated Column and Measure?
Calculated Column
- Computed during data refresh
- Stored in model
- Uses row context
Measure
- Calculated on the fly
- Better performance
- Uses filter context
16. What is Evaluation Context in DAX?
Types:
- Row Context
- Filter Context
- Context Transition
Understanding context is essential for mastering advanced DAX.
17. What is CROSSJOIN in DAX?
Answer:
CROSSJOIN returns the Cartesian product of two tables.
18. What is Power BI Gateway?
Answer:
A gateway connects on-premise databases to Power BI Service.
Types:
- Personal mode
- Enterprise mode
19. What is Aggregation Table?
Answer:
Aggregation tables store summarized data to improve performance for large datasets.
20. What are the Latest Features of Power BI (2025)?
Some of the advanced updates include:
- Hybrid tables
- Optimized DirectQuery
- New DAX functions (EVALUATEANDLOG, TOCSV, etc.)
- On-object interaction
- Fabric integration (2024–2025 update)
Scenario-Based Power BI Interview Questions (2025–2026)
21. Scenario: Your Power BI dashboard is slow. How do you optimize it?
Answer:
Steps to optimize:
- Reduce cardinality
- Use star schema
- Avoid heavy visuals
- Enable aggregations
- Use Import mode
- Optimize DAX
- Remove unnecessary columns
22. Scenario: You need to create a Year-to-Date (YTD) calculation. How?
Answer:
YTD Sales = TOTALYTD(SUM(Sales[Amount]), 'Date'[Date])23. Scenario: You want to show only the top 10 customers. How?
Use Top N filter → Select field → Top 10 → Apply measure (e.g., Total Sales).
24. Scenario: You want to merge two tables but keep all rows. Which join?
Answer:
Use Full Outer Join in Power Query.
25. Scenario: You need to show last month’s sales. Which DAX?
Last Month Sales =
CALCULATE(
SUM(Sales[Amount]),
PREVIOUSMONTH('Date'[Date])
)26. Scenario: Your DirectQuery report is not performing well. Solutions?
- Use aggregations
- Use performance analyzer
- Reduce visual interactions
- Avoid complex DAX
- Optimize source database
27. Scenario: You need to restrict data for certain users. What do you use?
Answer:
Use Row Level Security (RLS).
28. Scenario: You want to combine sales data from SQL Server and Excel. How?
Use Power Query → Transform Data → Merge/Append Queries.
29. Scenario: You need to create a custom calendar table. How?
DAX Calendar Table:
Calendar = CALENDAR (DATE(2020,1,1), DATE(2030,12,31))30. Scenario: You want to refresh data every hour. How?
Use Scheduled Refresh in Power BI Service
or Gateway + Incremental Refresh for large datasets.
Frequently Asked Power BI Concepts (Extra Useful for Interviews)
Data Modeling Best Practices (2025 & 2026)
- Follow star schema
- Avoid circular relationships
- Use surrogate keys
- Reduce bi-directional relationships unless necessary
Most Important DAX Functions to Learn
- CALCULATE
- FILTER
- SUMX
- RELATED / RELATEDTABLE
- SWITCH
- VAR
- ALL / ALLEXCEPT
- RANKX
Most Common Power BI Interview Topics in 2026
- Microsoft Fabric Integration
- Advanced DAX
- Direct Lake mode
- Incremental Refresh
- Paginated Reports
- Real-time dashboards
Power BI Interview Tips for 2025–2026
✔ Learn DAX deeply
✔ Understand star schema modeling
✔ Practice scenario-based questions
✔ Learn Power Query transformations
✔ Build at least 5–10 projects
✔ Stay updated with monthly Power BI updates
🎯 Conclusion
Preparing for Power BI interviews in 2025 and 2026 requires more than basic understanding—you must master DAX, data modeling, Power Query, performance optimization, and real-world scenarios.
This Top 30 Most Asked Power BI Interview Questions and Answers guide gives you a complete preparation blueprint for freshers, experienced professionals, BI developers, data analysts, and Power BI specialists.