Excel or Power BI: six signs a report should move, and what stays in Excel

Somewhere on a shared drive sits a file called Board pack March FINAL.xlsx, and next to it Board pack March FINAL (Sam's edits).xlsx. A useful spreadsheet became a monthly report, the report gained readers, and each reader got a copy. When someone then asks whether you should use Excel or Power BI, the real question is usually how to stop rebuilding that file every month.

The answer is rarely to give up Excel. It is to give each job to the tool built for it: Excel for working things out, Power BI for reports that come back every period for several readers.

An Excel workbook is a file. Every cell can hold a number or a formula, anyone who opens the file can change either, and every copy lives its own life. That freedom makes Excel the best tool there is for working things out.

Power BI turns this around. Power QueryPower QueryThe part of Excel and Power BI that fetches data from sources and cleans it, repeating the same recorded steps every time it runs. fetches the data from the source systems, a semantic modelSemantic modelThe layer in Power BI that holds the tables, the relationships between them and the calculations every report uses. It used to be called a dataset. holds it with fixed definitions, and readers see reports they can filter but not change. Builders work in Power BI Desktop, a free download (source: Microsoft, October 2026). Readers open the result in the Power BI service, Microsoft's cloud platform for publishing and sharing, in a browser or a mobile app (source: Microsoft, March 2026).

1. 1
   The same copy and paste every monthThe same exports, the same tabs, the same checks, by the one person who understands the file. Each round is a new chance of error: in more than 15,000 spreadsheets from the Enron email archive, 24% of those with formulas contained at least one Excel error value (source: Delft University of Technology, May 2015). Those are only the errors Excel displays; a total over the wrong range shows nothing.
2. 2
   Versions travel by emailSomeone updates a private copy, someone else forwards last week's, and the meeting opens with the question which file is right. One workbook in SharePoint or Teams helps; Power BI goes further, with one published report that changes only on refresh or on purpose.
3. 3
   The figures come from several systemsLedger, CRM (the customer system) and time tracking, matched by hand with lookups. Power BI fetches each source on every refresh and links the tables in the model, so the matching is built once.
4. 4
   The file has become heavyA worksheet stops at 1,048,576 rows (source: Microsoft, April 2026), and long before that a workbook full of lookups is slow to open, recalculate and send. In Power BI the data stays in the service and readers open only the report.
5. 5
   Not everyone may see everythingThe manager of the North region may see the North only. In Excel that means a file per reader, because Microsoft states that worksheet-level protection is not intended as a security feature (source: Microsoft, October 2025). Power BI uses row-level securityRow-level securityRules in the semantic model that filter which rows each signed-in reader sees. They restrict readers with the Viewer role, not the people who edit the workspace.: one report, and each reader sees only their own rows.
6. 6
   Readers want it current, and on their phonePower BI refreshes on a schedule, without anyone opening a file: up to eight times a day in a standard Pro workspaceWorkspaceA shared area in the Power BI service where a team builds, stores and shares models and reports., and up to 48 times with Premium Per User or on Premium or Fabric capacity (source: Microsoft, September 2026; Microsoft, August 2026). Readers can also use the mobile apps for iOS and Android (source: Microsoft, February 2026).

That freedom carries the risk described under the first sign: acceptable for a one-off analysis, not for a figure the board sees every month.

Power BI is a workload of Microsoft Fabric, Microsoft's wider data platform (source: Microsoft, March 2026), which is why licence pages mention Fabric.

Anyone who creates and shares content in a shared workspace needs Pro or Premium Per User (source: Microsoft, August 2026). Pro is included in Microsoft 365 E5 (source: Microsoft, November 2025), so check what you already pay for. With few readers, Pro for everyone is the usual start; capacity is worth comparing when many people only read.

1. 1Choose one reportThe one with the most manual work and an owner who decides on its content, such as monthly revenue and margin by region.
2. 2Agree the definitionsHow is each figure calculated, from which system? Revenue on invoice date or delivery date? Settling such differences is the most valuable part of the work.
3. 3Build and reconcileFetch the sources with Power Query, build the model and check the totals against the ledger for a closed month.
4. 4Run in parallelProduce one month-end close both ways and explain every difference.
5. 5Switch off the old fileArchive the workbook and tell readers where the report now lives. If both stay, both get used.

Model design, refresh and access rights are covered in Power BI setup and governance. Would you rather have the report built? Read having a Power BI dashboard built first. The other data guides are in IT and data.