CHARTS / PRACTICAL GUIDE
Waterfall chart: examples and when to use it
A waterfall chart shows how successive increases and decreases connect a starting total to an ending total. Floating bars show changes; total bars return to the baseline.
When to use it
Use it to explain a revenue bridge, a budget variance or a reconciliation. It answers which contributions account for the difference between two totals.
When to choose another view
Use a bar chart for independent category totals. Use a line chart for a continuous time series; a bridge is about contributions, not every observation along the way.
How to read it
Start at the opening total and add each signed change in order. A positive change raises the running level; a negative change lowers it. The closing bar should agree with the arithmetic.
Data format and example
A label, signed numeric value and role column. Mark the opening and closing rows as total and intermediate contributions as change.
| Step | Value | Type |
|---|---|---|
| Opening | 100 | total |
| Volume | 25 | change |
| Price | 12 | change |
| FX | -8 | change |
| Subtotal | 0 | subtotal |
| Other | 6 | change |
| Closing | 135 | total |
Make it in Datamon
- Prepare the opening total, each signed contribution and the closing total. Keep units consistent.
- Select Waterfall and map the label, value and role columns. Identify total rows explicitly.
- Check the sum: opening plus all changes must equal closing. Do not invent a balancing contribution.
- Use clear labels for increases and decreases. Add the scope and period to the subtitle.
Common mistakes to check
- Entering a total as a change double-counts it.
- A percentage-point change and a currency change cannot be added in the same bridge.
- An unexplained residual should be investigated and named, not hidden.