DAX is the point where most Power BI users hit a wall. The basics – dragging fields into a visual, formatting a chart, publishing a report – are learnable within a day. DAX is different. Data Analysis Expressions is a formula language with its own logic, and the most important and confusing part of it – filter context – is something that trips up even experienced Excel users. If you are searching for DAX training in London specifically, you are already at the stage where you know the basics are not enough.

What DAX Actually Is and Why It Is Hard

DAX is Power BI’s calculation engine. It is used to create measures (calculations that respond dynamically to filters and slicers), calculated columns (values that are computed row by row), and time intelligence functions (year-on-year comparisons, running totals, month-to-date figures) – functions especially valuable for finance team reporting. Without DAX, Power BI is a reporting tool. With DAX, it becomes a genuine business intelligence platform.

The difficulty is that DAX does not behave like Excel formulas. The same DAX expression can produce different results depending on which fields surround it in a visual – this is what is called filter context, and it is the concept that makes DAX click for some people and remain confusing for others. A good DAX course spends significant time on filter context, row context, and how functions like CALCULATE and FILTER modify them. A weak DAX course covers syntax and lists of functions without explaining the underlying logic.

London Providers Offering DAX-Specific Training

Acuity Training

Acuity offers both an Introduction to DAX and an Advanced DAX course, both available as online-only delivery. Their trainer for DAX – Oakley – has been a Microsoft Certified Trainer for eight years and has specialised in Power BI since 2017, with a specific focus on DAX scripting and advanced data modelling. The introductory course covers measures, calculated columns, context, and core functions including time intelligence. The advanced course goes further into complex calculations and performance optimisation using DAX Studio.

A useful structure: you do not need to be an advanced Power BI user to attend the introductory DAX course, but you should be comfortable with Power BI fundamentals. The two courses can be booked together with a £100 saving.

Best for: Power BI users who have completed an introduction course (or equivalent experience) and want to build serious DAX capability with a specialist trainer.

Wise Owl

Wise Owl run DAX-specific courses in London with a maximum class size of six. Their teaching approach is notable for the volume of free supporting material they publish openly – including YouTube tutorials and written exercises specifically on DAX topics – which lets you assess their teaching style before committing to a paid course. Their London classroom is near Liverpool Street, and their courses cover filter context, time intelligence, and iterator functions clearly. For delegates who learn well from written reference material, their free exercise library is a genuine post-course asset.

Best for: Delegates who want a small-group London classroom DAX course and appreciate being able to vet teaching quality through free materials first.

JBI Training

JBI’s DAX-specific course covers measures, calculated columns, time intelligence, and DAX Studio for debugging and performance analysis. The debugging section is genuinely useful – DAX errors can be cryptic, and knowing how to use DAX Studio to identify what a measure is calculating and where it is going wrong saves significant time in practice. Their trainers have delivered to BBC, Sky, and Lloyds Banking Group.

Best for: Technical users and BI developers who need DAX alongside a professional development record.

SQLBI (Mastering DAX Workshop)

For those who want to go beyond what any London provider offers on a standard course, SQLBI’s Mastering DAX Workshop is the most advanced DAX training available globally. It is a three-day classroom course taught by Marco Russo and Alberto Ferrari, the authors of The Definitive Guide to DAX. It runs in London periodically (most recently October 2025 at Tothill Street, SW1). All attendees receive a copy of the book.

This is not an introductory or intermediate course. SQLBI recommend a minimum of three to six months of DAX experience before attending, and suggest completing their free Introducing DAX video course first. It is aimed at Power BI developers, Power Pivot users, and Analysis Services professionals who want to master the language rather than learn to use it.

Best for: Experienced DAX users who want genuinely advanced instruction from the world’s foremost DAX specialists.

What Level of DAX Course Do You Need?

Introductory DAX is appropriate if you can navigate Power BI, build basic reports, but have not written measures beyond simple SUM or COUNT functions. You will come away understanding how measures work, what filter context means, and how to write the most common time intelligence calculations.

Advanced DAX is appropriate if you are already writing measures confidently and are hitting problems with complex scenarios – cumulative totals, dynamic titles, context transitions, or performance issues with large datasets.

SQLBI-level is for BI professionals building enterprise solutions where DAX performance, patterns, and architecture are genuine concerns.

Our Recommendation

For most London Power BI users looking to build solid DAX skills, Acuity Training’s Introduction to DAX course is the right starting point. Microsoft-certified delivery, a specialist trainer with eight years of MCT experience and deep Power BI focus since 2017, and six months of post-course support make it a strong package. For those ready for the next level, the Advanced DAX course builds directly on it. For a broader comparison of Power BI training providers in London, see our shortlist of the best Power BI courses in London.