Show Value As in Power BI - Percentages and Running Totals Without Writing DAX

A lot of the reporting questions businesses actually ask are not about raw numbers. Nobody in a leadership meeting cares that the Sydney office did 4.2 million in a vacuum. They care that Sydney is 38 per cent of the national total, or that it is up on last quarter, or that year to date it has already passed where it finished last year. Those are relative numbers, and the good news is that Power BI can produce a lot of them without you writing a line of DAX. The feature is called Show value as, and it is one of the most underused things in the product.

I want to walk through what Show value as can do, where it saves you real time, and the point where you should stop fighting it and write a proper measure instead. Microsoft's documentation on Show value as lists the options. What I want to add is the judgement about when each one holds up and when it quietly lies to you.

What it actually does

Show value as takes a value you have already dropped into a visual and recalculates how it is displayed relative to something else. You right-click the field in the visual, choose Show value as, and pick from a menu. The most common options are percentage of grand total, percentage of column or row total, running total, and difference or percentage difference from a previous value.

The key thing to understand is that it is a display transformation on top of whatever is in the visual. It does not create a new field in your model. It changes how that one visual presents the number, using the rows and columns already in the visual as the frame of reference. That is both the appeal and the limitation, and most of the trouble people have with it comes from not keeping that in mind.

The options I actually use

Percentage of grand total is the workhorse. You have sales by state in a table, you want each state as a share of the national number, one click and you have it. This is the one I reach for constantly, because "what share of the total is this" is such a common business question and building it in DAX every time is a waste.

Percentage of row total and percentage of column total are the matrix versions. If you have a matrix of product category down the side and region across the top, percentage of row total tells you how each product's sales split across regions, and percentage of column total tells you the product mix within each region. Same data, two completely different questions, and you switch between them with a right-click. That flexibility is genuinely handy in a review meeting when someone asks the question the other way around.

Running total is the one people forget exists. Cumulative sales across months, a running headcount, progress toward an annual target. You put the value in a table by month, set it to running total over the date field, and you get the cumulative line without a SUMX over a filtered date range. For a quick "where are we tracking" view it is perfect.

Difference from and percentage difference from compare each value to another value in the same field, usually the previous one. Month-on-month change, for instance. It works, and for a fast look it is fine.

Where it saves you real time

The honest pitch for Show value as is speed. During report building, and especially during those live sessions where a stakeholder is looking over your shoulder asking "can you show that as a percentage," being able to right-click and reframe the number instantly is worth a lot. You keep the conversation moving instead of disappearing into the formula bar.

It is also good for exploration. When you are still working out how someone wants to see the data, flipping between grand total, row total and running total to find the view that lands is far faster with a menu than with three separate measures you then have to delete. Get the shape agreed, then decide what to make permanent.

And for simple, self-contained tables it is completely fine to ship. A table of regional revenue with a "percentage of total" column built this way is perfectly legitimate. Not everything needs a measure.

Where you should stop and write DAX

Here is where I get cautious, because Show value as has real limits and I have seen reports go wrong by leaning on it too hard.

The first problem is that the result is trapped in the visual. You cannot reference a Show value as result in another measure, you cannot use it in a calculation, and you cannot reuse it on another page without setting it up again. The moment you need that percentage anywhere else, you need a real measure. If a number is going to be used more than once, write the DAX and be done with it.

The second is that the frame of reference is whatever happens to be in the visual, which makes it fragile. Percentage of grand total means grand total of the rows currently shown, after filters and slicers. That is often what you want, but not always. Someone applies a slicer, the "total" quietly becomes the total of the filtered set, and the percentages shift under people without anyone noticing. A properly written measure with explicit ALL or ALLSELECTED gives you control over exactly what the denominator is. Show value as gives you whatever the visual context happens to be, and you have to be sure that is what you meant.

The third is that the useful options run out fast. Year-to-date that respects your fiscal year, same period last year, a percentage of a specific parent level rather than the visible one, comparisons across a disconnected date table. The real business questions get more specific than the menu, and once you are past the basics you are in DAX territory whether you like it or not. Time intelligence in particular is almost always better as explicit measures, especially in Australia where the July-to-June financial year trips up anything that assumes a calendar year.

And there is a maintainability angle that matters on a team. A Show value as setting is buried in one visual's configuration. Another developer opening the report has to click into the field to discover the number is a running total and not a raw sum. A named measure, Sales Running Total, is self-documenting. On a report that more than one person maintains, that clarity is worth the extra few minutes.

My rule of thumb

Use Show value as freely while you are building and exploring, and use it in simple standalone tables where the number only needs to exist in that one place. The moment a relative number needs to be reused, needs a denominator you control, or involves anything to do with fiscal periods, write a measure. It is not a competition between the two. The menu is for speed and the DAX is for the numbers you are going to rely on.

This distinction, quick display trick versus a real measure the business depends on, is exactly the kind of thing we sort out in our Power BI consulting work, usually while cleaning up a report where a slicer quietly broke half the percentages. It is part of the wider business intelligence work we do, and it tends to lead into proper data modelling on the Microsoft Fabric platform, because clean, reusable measures are a modelling decision more than a report one.

If you have got Power BI reports where the percentages do not quite add up, or you want reporting built with the numbers defined properly the first time, take a look at our services or get in touch.