Data warehouse or Excel? When it's time to take the next step

Excel is a brilliant tool. In many companies it has held reporting, planning and operations together for years. The question is when it becomes a bottleneck and when it’s time to build a full data warehouse.

5 signs you’re already “beyond Excel”

1. The monthly closing takes longer than a week

If an accountant merges exports from the ERP, CRM and external systems every month and matching them by hand takes 5+ working days, that’s a strong signal.

2. There are 3 versions of the truth about the same number

The CFO has a different revenue figure in their report than the sales director, and marketing has a third. None of them are acting in bad faith - they just each combine the data differently.

3. Employees are afraid a colleague will leave

When the entire Excel reporting lives in one person’s head (and no one else can edit it), that’s an operational risk, not a sign of experience.

4. New analytical questions take weeks

“What is our average delivery time per customer over the last year by product category?” - if the answer is “we’ll get that to you in 3 weeks”, you have a problem.

5. You have Power BI, but it’s “glued on” via Excel

Power BI works best on top of a data model, not on top of manually prepared Excel exports. If Excel is the intermediate step, it’s a temporary solution.

What a data warehouse solves

• One source of truth. All the numbers come from the same model.
• Historisation. You know what the data looked like a year ago - not just the current state.
• Speed. Optimised for analytical queries over millions of rows.
• Automation. No manual gluing every month.
• Independence from any one person. The data flow is documented and runs on its own.

And when you DON’T need it

1. You’re a small company with a single system

If you have 15 employees, everything runs in one ERP and the reports are clear, a full DWH is overkill. A well-configured Power BI directly on top of the ERP is enough.

2. The data doesn’t change in volume or complexity

If your reporting has worked for 5 years without change and no one has any complaints, there’s no reason to change it.

3. You don’t have people who will use it

The best data warehouse is useless if no one looks for answers in it. First grow data-literate users, then build the infrastructure.

How to start

A data warehouse doesn’t have to be a year-long project. Our typical strategy:

1. Workshop (1 week) - understand what and why we’re building.
2. MVP (6-10 weeks) - a first usable warehouse with 1-2 domains (e.g. finance and sales).
3. Iterative expansion - more domains, deeper historisation, more reports.

Always with a visible output every month.

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Thinking about a data warehouse? See our services or write to us - we’ll prepare a no-obligation estimate.