Waterfall charts in Power BI - Cell-by-Cell Formula Trace

Sample Data

This data shows categories and their amounts for a waterfall chart. 'Start' is the initial value, followed by positive and negative changes, and 'End' is the final total to calculate.

Cell	Value
A1	Category
B1	Amount
A2	Start
B2	1000
A3	Sales
B3	300
A4	Returns
B4	-100
A5	Expenses
B5	-200
A6	End
B6	1000

Formula Trace

End = Start + Sales + Returns + Expenses

Step 1: Start

Step 2: Start + Sales

Step 3: 1300 + Returns

Step 4: 1200 + Expenses

Step 5: End

Cell Reference Map

    A       B
  +-------+-------+
1 |Category|Amount |
  +-------+-------+
2 | Start  | 1000  | <-- Start value
  +-------+-------+
3 | Sales  |  300  | <-- Sales increase
  +-------+-------+
4 | Returns| -100  | <-- Returns decrease
  +-------+-------+
5 |Expenses| -200  | <-- Expenses decrease
  +-------+-------+
6 | End    | 1000  | <-- End to calculate
  +-------+-------+

Cells B2 to B5 provide the amounts for the waterfall calculation. B6 is where the final total (End) is calculated by summing these values.

Result

    A       B
  +-------+-------+
1 |Category|Amount |
  +-------+-------+
2 | Start  | 1000  |
  +-------+-------+
3 | Sales  |  300  |
  +-------+-------+
4 | Returns| -100  |
  +-------+-------+
5 |Expenses| -200  |
  +-------+-------+
6 | End    | 1000  |
  +-------+-------+

The final result shows the End value as 1000 in cell B6, which is the sum of Start plus all changes (Sales, Returns, Expenses). This value is used in the waterfall chart to show the final total after all increases and decreases.

Sheet Trace Quiz - 3 Questions

What is the value of the 'End' after adding Sales to Start?

A 300

B 1000

C 1300

D 1200

Key Result

Waterfall chart totals are calculated by starting with an initial value and adding or subtracting each category's amount step by step.

Practice

1. What is the main purpose of a Waterfall chart in Power BI?

easy

A. To compare two unrelated categories side by side

B. To show how individual values add or subtract to reach a total

C. To display data in a pie format

D. To show only positive values over time

Solution

1. Step 1: Understand Waterfall chart purpose

   Waterfall charts visualize how starting values change step-by-step by additions or subtractions to reach an end value.

2. Step 2: Compare options with this purpose

   Only To show how individual values add or subtract to reach a total describes this stepwise addition and subtraction clearly.

3. Final Answer:

   To show how individual values add or subtract to reach a total -> Option B

4. Quick Check:

   Waterfall charts = stepwise changes [OK]

Hint: Think: How does value move from start to end? [OK]

Common Mistakes:

• Confusing Waterfall with Pie chart
• Thinking it only shows positive values
• Assuming it compares unrelated categories

2. Which of the following is the correct way to assign fields when creating a Waterfall chart in Power BI?

easy

A. Assign 'Date' to the legend and 'Category' to the values field

B. Assign 'Value' to the axis and 'Category' to the values field

C. Assign 'Category' to the axis and 'Value' to the values field

D. Assign 'Category' to the tooltip and 'Value' to the legend

Solution

1. Step 1: Identify correct field roles for Waterfall chart

   The category field defines the steps on the axis, and the value field shows the amount added or subtracted.

2. Step 2: Match options to correct roles

   Assign 'Category' to the axis and 'Value' to the values field correctly assigns 'Category' to axis and 'Value' to values field, which is required for Waterfall charts.

3. Final Answer:

   Assign 'Category' to the axis and 'Value' to the values field -> Option C

4. Quick Check:

   Category = axis, Value = values [OK]

Hint: Category goes on axis, values show changes [OK]

Common Mistakes:

• Swapping category and value fields
• Using date or legend incorrectly
• Assigning category to tooltip instead of axis

3. Given the following data:

Category | Value
Start    | 100
Sales    | 50
Returns  | -20
Expenses | -30
End      | ?

What will be the final 'End' value shown in the Waterfall chart?

medium

A. 100 + 50 - 20 - 30 = 100

B. 100

C. 100 + 50 - 20 - 30 = 100 but End is 0

D. 100 + 50 - 20 - 30 = 100 but End is 100

Solution

1. Step 1: Calculate stepwise changes

   Start at 100, add 50 (Sales) -> 150, subtract 20 (Returns) -> 130, subtract 30 (Expenses) -> 100.

2. Step 2: Determine final End value

   The End value is the total after all changes, which is 100.

3. Final Answer:

   100 + 50 - 20 - 30 = 100 -> Option A

4. Quick Check:

   Sum changes = 100 [OK]

Hint: Add positives, subtract negatives stepwise [OK]

Common Mistakes:

• Ignoring negative values as subtractions
• Assuming End is zero by default
• Adding values incorrectly

4. You created a Waterfall chart but it shows all bars as positive values, even though some values are negative. What is the most likely cause?

medium

A. You applied a filter that removes negative values

B. You assigned the 'Value' field as text instead of number

C. You forgot to add the 'Category' field to the axis

D. You used a measure that returns absolute values instead of signed values

Solution

1. Step 1: Analyze why negatives appear positive

   If the measure returns absolute values, negatives become positive, causing all bars to show as positive.

2. Step 2: Check other options

   Other options don't match: assigning values as text would prevent numerical display or cause errors, missing category on axis would disrupt chart structure, a filter removing negatives would eliminate those bars entirely rather than showing them as positive.

3. Final Answer:

   You used a measure that returns absolute values instead of signed values -> Option D

4. Quick Check:

   Absolute values hide negatives [OK]

Hint: Check if measure uses ABS() or similar function [OK]

Common Mistakes:

• Confusing data type errors with value sign issues
• Ignoring measure logic
• Assuming missing category causes positive bars

5. You want to create a Waterfall chart showing monthly profit changes, but your data has some months missing. How should you prepare your data to ensure the Waterfall chart shows all months in order with correct step changes?

hard

A. Fill missing months with zero profit and sort by month

B. Remove months with no data to avoid confusion

C. Use a pie chart instead to avoid missing months

D. Manually add missing months as negative values

Solution

1. Step 1: Understand missing data impact on Waterfall chart

   Missing months cause gaps in the axis and incorrect step calculations.

2. Step 2: Prepare data by filling missing months

   Fill missing months with zero profit so the chart shows continuous months and correct cumulative changes.

3. Step 3: Sort data by month

   Sorting ensures the Waterfall steps follow the correct time order.

4. Final Answer:

   Fill missing months with zero profit and sort by month -> Option A

5. Quick Check:

   Fill gaps with zero and sort [OK]

Hint: Fill missing steps with zero to keep continuity [OK]

Common Mistakes:

• Removing missing months causing gaps
• Using wrong chart type
• Adding fake negative values