60 Power BI Interview Questions and Answers for 2026

Power BI developers transform raw data into interactive reports and dashboards that drive decision-making across organizations. Hiring the right BI professional means assessing DAX proficiency, data modeling expertise, and visualization skills alongside the ability to translate business requirements into actionable insights.

Effective Power BI interviews evaluate both technical depth and practical implementation experience. The questions in this guide cover fundamentals for beginners, intermediate concepts, advanced DAX functions, and scenario-based problems that reveal whether candidates can deliver real-world business intelligence solutions.

Whether you're building an ultimate interview process or preparing as a candidate, these power bi interview questions and answers provide comprehensive coverage of what matters in BI roles.

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What Is Power BI?

Microsoft Power BI is a business intelligence tool enabling users to connect to data sources, transform data, build data models, and create interactive reports and dashboards. The platform consists of several components of power bi working together.

Power BI Desktop is the free development environment where you build reports. Power BI Service is the cloud-based platform for publishing, sharing, and collaboration. Power BI Gateway connects the service to on-premises data sources like SQL Server and Oracle. Power BI Premium offers dedicated capacity for large datasets and advanced features.

The platform integrates with the broader Microsoft ecosystem including Excel, Azure, and SharePoint, making it popular for organizations already invested in Microsoft technologies.

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Basic Power BI Interview Questions

1. What is Power BI and why use Power BI?

Power BI is Microsoft's business intelligence tool for connecting to data, transforming it, building models, and creating visualizations. Benefits include self-service BI capabilities, lower cost than Tableau, natural language queries, and tight integration with Microsoft products.

2. What are the major components of Power BI?

Key components include: Power BI Desktop (authoring), Power BI Service (publishing and sharing), Power BI Mobile (mobile access), Power BI Gateway (on-premises data connectivity), Power BI Embedded (embedding in applications), and Power BI Report Server (on-premises deployment).

3. What is Power Query?

Power Query is the ETL engine for data transformation and preparation. Using the query editor, you can connect to data sources, clean raw data, transform shapes, and create reusable steps. M language powers the transformations behind the visual interface.

4. What is Power Pivot?

Power Pivot is the data modeling engine enabling relationships between tables, calculated columns, measures, and KPIs. It uses the xVelocity in-memory analytics engine for fast calculations on large datasets.

5. What is DAX?

DAX (Data Analysis Expressions) is the formula language for creating calculated columns, measures, and calculated tables. DAX functions are similar to Excel formulas but designed for relational data models and aggregate calculations.

6. What data sources can Power BI connect to?

Power BI supports 100+ connectors including: files (Excel, CSV), databases (SQL Server, Oracle), online services (Salesforce, Google Analytics), and Azure services. Data connectivity options accommodate most enterprise data environments.

7. What is the difference between a report and a dashboard?

Power BI reports are multi-page interactive reports created in Power BI Desktop containing visualizations from a single dataset. A Power BI dashboard is a single-page canvas in Power BI Service with tiles pinned from multiple reports and datasets.

8. What connectivity modes are available?

Import mode loads data into Power BI memory. Direct query sends queries to the source in real-time. Live connection connects to Analysis Services or Power BI datasets. Composite models combine import mode and DirectQuery.

9. What views are available in Power BI Desktop?

Report view is for designing visualizations. Data view allows inspecting and exploring tables. Model view manages relationships between tables. Each view serves different development purposes.

10. What are filters in Power BI?

Visual-level filters affect single visuals. Page-level filters affect all visuals on a report page. Report-level filters affect all pages. Drill-through filters enable navigation to detailed pages based on context.

11. What are slicers?

Slicers are visual filter controls on the report canvas allowing users to interactively filter data. Unlike the filter pane, slicers are visible to report consumers and provide intuitive filtering.

12. How do you refresh data?

Manual data refresh happens on-demand. Scheduled refresh runs automatically (8 times daily for Power BI Pro, 48 for Premium). Power BI Gateway is required for on-premises sources. Dataflows enable centralized refresh.

13. What's the difference between Free, Pro, and Premium?

Free allows desktop development with limited sharing. Power BI Pro enables full collaboration and sharing with 1GB model limits. Power BI Premium provides dedicated capacity, larger models, and advanced features like paginated reports.

14. How does Power BI compare to Tableau?

Power BI offers better Microsoft integration and lower cost. Tableau provides more advanced data visualization options and is platform-agnostic. Power BI uses DAX; Tableau uses VizQL. Choice depends on existing technology stack.

15. How does Power BI compare to Excel?

Excel suits ad-hoc data analysis and smaller datasets. Power BI handles larger datasets, provides better visualization, enables sharing through workspace collaboration, and offers automatic refresh. Both share Power Query and Power Pivot foundations.

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DAX Interview Questions

16. What is the difference between calculated columns and measures?

Calculated columns compute row-by-row during data refresh, storing values and consuming memory. Measures calculate at query time based on filter context, providing more efficient aggregate calculations.

17. When should you use calculated columns vs. measures?

Use calculated columns for row-level values needed for slicing or when calculation depends only on current row. Use measures for aggregations, ratios, and calculations responding to filter context.

18. What is the CALCULATE function?

The calculate function is the most important DAX function, modifying filter context for expressions. Syntax: CALCULATE(expression, filter1, filter2...). It enables complex calculations by changing context.

19. Explain Row Context and Filter Context.

Row context exists during row-by-row evaluation in calculated columns and iterators like SUMX. Filter context is the set of filters applied from slicers, filters, and visual context. Understanding both is essential for DAX mastery.

20. What is the difference between SUM and SUMX?

SUM aggregates a column directly. SUMX iterates through rows, evaluates an expression for each, then sums results. SUMX creates row context, enabling row-level calculations before aggregation.

21. What are time intelligence functions?

Time intelligence functions handle date-based calculations: TOTALYTD, SAMEPERIODLASTYEAR, DATEADD for period comparisons. They require a proper date table with continuous dates.

22. What is the ALL function?

ALL removes filters from specified columns or tables, returning all values regardless of context. Common uses include calculating percentages of total and comparing values to overall figures.

23. What are variables in DAX formulas?

Variables (VAR keyword) store intermediate results. Benefits include improved readability, better performance (expression evaluated once), and easier debugging. Syntax: VAR name = expression RETURN result.

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Data Modeling Questions

24. What is a star schema?

Star schema places a central fact table surrounded by dimension tables. Benefits include simpler models, better performance, intuitive navigation, and more efficient DAX. It's the recommended approach for Power BI data modeling.

25. What are Fact Tables and Dimension Tables?

Fact tables contain measurable events (sales, orders) with numeric values and foreign keys. Dimension tables contain descriptive attributes (products, customers, dates) for filtering and grouping metrics.

26. What relationship types exist in Power BI?

One-to-many relationships are most common (dimension to fact). One-to-one relationships are rare. Many-to-many relationships require careful handling to avoid ambiguous results and performance issues.

27. What is bi-directional cross-filtering?

Bi-directional filtering allows filters to flow both directions in a relationship. Risks include ambiguous paths and performance impact. Single direction is recommended when possible.

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

RLS restricts data access at row level based on user identity. Static RLS uses defined roles with DAX filters. Dynamic RLS uses USERNAME() or USERPRINCIPALNAME() for user-specific filtering.

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Intermediate Questions

29. What is query folding?

Query folding pushes Power Query transformation steps back to the data source for server-side processing. This improves performance and reduces memory usage. Some transformations break folding.

30. What is M language?

M is the functional language behind Power Query transformations. The Advanced Editor reveals M code for complex transformations beyond the visual interface capabilities.

31. What's the difference between Append and Merge?

Append combines tables vertically, stacking rows like SQL UNION. Merge combines tables horizontally like SQL JOIN, matching on columns. Different merge types include inner, left outer, and full outer.

32. What are custom visuals?

Custom visuals extend default visualization options. Sources include AppSource marketplace, organizational visuals, and custom development using the Power BI Visuals SDK.

33. What is a workspace?

A workspace is a container for organizing and collaborating on reports, dashboards, and datasets. Roles include Admin, Member, Contributor, and Viewer with different permissions.

34. What is Power BI Gateway?

Power BI Gateway bridges Power BI Service to on-premises data sources. Standard gateway is shared and centrally managed. Personal gateway serves single users.

35. What are KPIs?

KPIs (Key Performance Indicators) are visual indicators showing progress toward goals. Components include base value, target value, and status thresholds displayed through graphs and indicators.

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Advanced Questions

36. How do you optimize Power BI reports?

Optimization strategies include: proper star schema modeling, removing unused columns, using variables in DAX formulas, implementing aggregations, limiting visuals per page, and using Performance Analyzer.

37. What are dataflows?

Dataflows provide reusable ETL logic stored in Power BI Service. Benefits include centralized data preparation, reduced redundancy across datasets, and computed entities for complex transformations.

38. What is an incremental refresh?

Incremental refresh updates only new or changed data rather than entire datasets. Configuration requires RangeStart/RangeEnd parameters. Available for Pro and Premium licenses.

39. What are composite models?

Composite models combine import mode and DirectQuery tables. Use cases include large historical data (import) with real-time current data (DirectQuery) for balanced performance.

40. What is the What-If parameter?

What-If parameters create numeric slicers for scenario analysis without underlying data. Useful for sensitivity analysis and forecasting different business scenarios.

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Scenario-Based Questions

41. Your report is running slowly. How do you diagnose it?

Use Performance Analyzer to identify slow visuals and queries. Check data modeling for many-to-many relationships and bi-directional filtering. Review DAX measures for complexity. Consider aggregations for large datasets.

42. How would you merge data from systems with inconsistent formats?

In Power Query: standardize data types, handle null values, create common keys through transformations, use appropriate merge type, and handle duplicate records before loading to the model.

43. Regional managers should only see their region's data. How do you implement this?

Implement row-level security: define roles in Power BI Desktop, create DAX filter using USERPRINCIPALNAME(), assign users to roles in Power BI Service, test with "View as Role" feature.

44. How would you create a dynamic title based on slicer selections?

Create a measure using SELECTEDVALUE or CONCATENATEX to capture selected values. Use the measure in a text visual or card, or enable dynamic titles in visual formatting options.

45. How do you implement year-over-year comparisons?

Use time intelligence functions: SAMEPERIODLASTYEAR for simple comparisons, DATEADD for flexible offsets. Create measures calculating current period, prior period, and percentage change.

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Tips for Conducting Power BI Interviews

Balance Technical and Business Skills

Power BI roles require both technical proficiency and understanding business requirements. Assess DAX knowledge alongside ability to translate stakeholder needs into effective data visualization.

Include Practical Assessments

Hands-on exercises reveal true capability. Ask candidates to build a report, write DAX measures for specific requirements, or optimize a slow dashboard using sample data.

Assess Data Modeling Understanding

Proper data modeling is foundational. Evaluate candidates' ability to design star schemas, understand relationships, and recognize modeling problems. Companies hiring remote workers especially benefit from candidates who can work independently on complex models.

Evaluate Communication Skills

Power BI developers must explain insights to stakeholders. Assess ability to communicate technical concepts clearly. Look for candidates who can spot growth mindset in interviews and continuously learn.

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Tips for Candidates

Master DAX Fundamentals

Deep understanding of CALCULATE, filter context, row context, and iterator functions is essential. These concepts underpin advanced Power BI work and distinguish data analyst professionals.

Practice Data Modeling

Build star schemas, understand fact and dimension tables, recognize common patterns. Modeling skills determine report performance and calculation accuracy.

Build a Portfolio

Create sample reports demonstrating DAX complexity, good design, performance optimization, and various visualization types including interactive reports with drill-through navigation.

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FAQs

What skills matter most for Power BI roles?

DAX proficiency, data modeling understanding, Power Query transformations, visualization best practices, and SQL knowledge for data science integration.

Should I test DAX writing skills?

Yes. Asking candidates to write measures for specific scenarios reveals true understanding beyond memorized definitions of dax functions.

What certifications help?

Microsoft PL-300 (Power BI Data Analyst) and DP-600 (Fabric Analytics Engineer). Practical experience often matters more than certifications.

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Great Interview Questions Find Great BI Professionals. Great Recruiting Finds Candidates Worth Interviewing.

These questions help you evaluate Power BI candidates effectively. But they only help when you have qualified candidates to interview in the first place.

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Great interview questions help you evaluate candidates. Great recruiting ensures you have candidates worth evaluating.

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