Profit and loss account

Context

A P&L is one of the most important reports for understanding a business.

A profit and loss account (P&L) summarises a company’s revenue, costs and expenses over a period and shows what the final result has been.

In theory, it looks simple. In practice, a P&L can have many lines, levels and relationships between items.

When I took it into Power BI, my challenge wasn’t simply getting the numbers to appear in a table. I wanted to be able to explore them without losing the financial logic behind each figure.

What is a P&L?

Before getting into Power BI: what is a profit and loss account?

A profit and loss account (P&L) helps you understand how a business has performed financially over a period. Put simply:

Revenue − costs and expenses = result

But a real P&L has many more lines and levels. The final result depends on all the items behind it.

That’s why, when a figure changes, the interesting question isn’t just how much it has changed, but also which items explain that change.

That’s exactly what I wanted to be able to explore with this project.

Target

I wanted a P&L I could explore without losing context.

My aim was to build a financial report that lets you move from an overview of the result to the detail that explains it. To do that, I worked with two main needs: looking at the P&L at different levels of detail, and understanding which items lie behind each result.

That way, the report doesn’t just show a figure: it lets you follow the path until you understand where it comes from.

Model

I built the model from the accounting logic, not from the visual.

Before designing the dashboard, I first had to understand how the financial information was organised. A P&L isn’t just a list of numbers: each line has a meaning and is part of a structure of revenue, costs, expenses and results.

That’s why I first organised the data following that logic, and then built the visuals on top of the model.

Data model

A central fact table and six dimensions.

Visualisation

Two ways to read the same information.

A P&L can answer different questions depending on how you look at it. That’s why I built two complementary views.

Expandable P&L — a view designed to start from the overall result and gradually open each level down to the detail. It lets me go from a total figure to the items that make it up without changing context.

Detail with waterfall — a view focused on understanding how the different items contribute to the final result. The waterfall chart helps show which items increase or reduce the result on the way to the final figure.

I didn’t want two different visuals just for the sake of it. Each one answers a question: where am I? and what is explaining this result?

Comparison

The same result can tell a different story depending on how you look at it.

The total answers «how much». The detail helps answer «why».

Tech stack

The tools I used

Challenge

The hard part wasn’t just the visual. It was keeping the meaning of every figure.

In a P&L, the sign of an amount matters. Revenue and expenses don’t behave the same way in the calculation of the result. If that logic isn’t kept correctly, a figure that looks right can end up telling the wrong story.

That’s why I paid special attention to how signs were handled in the model, in the measures and finally in the visuals.

This was one of the most important lessons of the project: in a financial report, the number being right isn’t always enough. It also has to be shown the right way.