Dual axis charts in Tableau - Step-by-Step Guide

Introduction

Dual axis charts let you show two different measures on the same chart using two vertical axes. This helps compare related data with different scales clearly in one view.

When you want to compare sales revenue and number of units sold on the same timeline.

When you need to show temperature and rainfall together on a weather dashboard.

When you want to display profit margin and total sales side by side for each product category.

When you want to combine actual sales and sales target in one chart for easy comparison.

When you want to visualize website visits and conversion rate on the same graph.

Steps

Step 1: Drag the first measure (e.g., Sales) to Rows shelf

- Rows shelf

A single-axis chart with the first measure appears on the view

Step 2: Drag the second measure (e.g., Profit) to the right side of the existing axis on Rows shelf

- Rows shelf, next to the first measure

Two separate charts appear stacked vertically, each with its own axis

Step 3: Right-click the second measure's axis and select 'Dual Axis'

- Second measure's axis on the view

Both measures share the same horizontal axis but have separate vertical axes, overlapping in one chart

Step 4: Click the drop-down arrow on the Marks card and select each measure to customize colors or chart types

- Marks card

Each measure can have different colors or chart types (e.g., bars and lines) for clarity

Step 5: Right-click one of the axes and select 'Synchronize Axis' if scales should match

- One of the vertical axes

Both axes use the same scale, making comparison easier

Step 6: Format axes and labels as needed for clarity

- Axes and Labels on the view

The chart looks clear and easy to read with proper labels and formatting

Before vs After

Before

Two separate charts stacked vertically: Sales with axis 0-10000, Profit with axis 0-2000

After

One combined chart with Sales and Profit overlaid, each with its own vertical axis on left and right

Settings Reference

Dual Axis

📍 Right-click on second measure's axis in the view

Combine two measures on one chart with two vertical axes

Default: Separate Axis

Synchronize Axis

📍 Right-click on one of the vertical axes

Make both axes use the same scale for easier comparison

Default: Unsynchronize

Marks Type

📍 Marks card for each measure

Choose how each measure is visually represented on the chart

Default: Automatic

Common Mistakes

Not selecting 'Dual Axis' after adding the second measure

The measures remain in separate charts stacked vertically, not combined

Right-click the second measure's axis and choose 'Dual Axis' to overlay them

Forgetting to synchronize axes when scales are similar

Axes have different scales, making visual comparison confusing

Right-click one axis and select 'Synchronize Axis' to align scales

Using the same mark type and color for both measures

It becomes hard to distinguish which data belongs to which measure

Use different mark types or colors for each measure on the Marks card

Summary

Dual axis charts overlay two measures with separate vertical axes on one chart.

They help compare related data with different scales clearly in one view.

Remember to use 'Dual Axis' and optionally 'Synchronize Axis' for best clarity.

Practice

1. What is the main purpose of a dual axis chart in Tableau?

easy

A. To filter data based on two conditions

B. To create two separate charts side by side

C. To compare two different measures on the same graph using two axes

D. To combine two dimensions into one axis

Solution

1. Step 1: Understand what dual axis means

   A dual axis chart shows two measures on one graph but with two separate axes, usually one on the left and one on the right.

2. Step 2: Compare options with this definition

   Only To compare two different measures on the same graph using two axes describes comparing two measures on the same graph using two axes, which matches the definition.

3. Final Answer:

   To compare two different measures on the same graph using two axes -> Option C

4. Quick Check:

   Dual axis = compare two measures on one graph [OK]

Hint: Dual axis means two measures, two axes on one chart [OK]

Common Mistakes:

• Thinking dual axis creates two separate charts
• Confusing dual axis with filtering
• Mixing up dimensions and measures

2. Which of the following is the correct way to create a dual axis chart in Tableau?

easy

A. Drag one measure to Filters and one measure to Tooltip, then select 'Dual Axis'

B. Drag one measure to Columns and one dimension to Rows, then select 'Dual Axis'

C. Drag two dimensions to Rows shelf and select 'Dual Axis'

D. Drag two measures to Rows shelf, right-click second measure, and select 'Dual Axis'

Solution

1. Step 1: Recall the dual axis creation steps

   To create a dual axis chart, you drag two measures to the Rows or Columns shelf, then right-click the second measure and choose 'Dual Axis'.

2. Step 2: Check each option

   Drag two measures to Rows shelf, right-click second measure, and select 'Dual Axis' matches the correct method. The other options misuse dimensions or shelves and do not create dual axis charts.

3. Final Answer:

   Drag two measures to Rows shelf, right-click second measure, and select 'Dual Axis' -> Option D

4. Quick Check:

   Drag two measures + Dual Axis = correct method [OK]

Hint: Drag two measures, right-click second, pick 'Dual Axis' [OK]

Common Mistakes:

• Using dimensions instead of measures for dual axis
• Trying to dual axis with filters or tooltips
• Not right-clicking the second measure

3. Given a dual axis chart with Sales on the left axis and Profit on the right axis, what happens if you do NOT synchronize the axes?

medium

A. The chart will show an error and not display

B. The two measures may appear on different scales, making comparison misleading

C. Both axes will automatically use the same scale

D. The marks for both measures will merge into one

Solution

1. Step 1: Understand axis synchronization

   Synchronizing axes means making both axes use the same scale so the measures can be compared fairly.

2. Step 2: Consider what happens without synchronization

   Without synchronization, each axis uses its own scale, so the measures may look very different even if values are similar, causing misleading visuals.

3. Final Answer:

   The two measures may appear on different scales, making comparison misleading -> Option B

4. Quick Check:

   Unsynchronized axes = different scales, misleading comparison [OK]

Hint: Unsync axes = different scales, hard to compare [OK]

Common Mistakes:

• Assuming Tableau auto-syncs axes always
• Thinking chart shows error without sync
• Believing marks merge automatically

4. You created a dual axis chart but the marks for the second measure do not appear. What is the most likely cause?

medium

A. You did not assign a mark type to the second axis

B. You forgot to synchronize the axes

C. You dragged a dimension instead of a measure for the second axis

D. You did not drag the second measure to the Tooltip shelf

Solution

1. Step 1: Check mark types for dual axis

   Each axis in a dual axis chart needs a mark type (like bar, line) assigned to show its data points.

2. Step 2: Identify why marks might be missing

   If the second axis has no mark type assigned, its marks won't display even if data is present.

3. Final Answer:

   You did not assign a mark type to the second axis -> Option A

4. Quick Check:

   No mark type = no marks shown [OK]

Hint: Assign mark type to each axis to show marks [OK]

Common Mistakes:

• Confusing axis sync with mark visibility
• Dragging dimensions instead of measures
• Thinking Tooltip shelf controls marks

5. You want to create a dual axis chart comparing monthly Sales (as bars) and Profit Ratio (as a line) over a year. Which steps correctly achieve this?

hard

A. Drag Sales and Profit Ratio to Rows, right-click Profit Ratio and select 'Dual Axis', then set Sales marks to Bar and Profit Ratio marks to Line

B. Drag Sales to Columns and Profit Ratio to Rows, then combine using 'Dual Axis', set both marks to Bar

C. Drag Sales and Profit Ratio to Rows, synchronize axes, then set both marks to Line

D. Drag Sales to Rows, Profit Ratio to Tooltip, then select 'Dual Axis' and set marks to Bar and Line

Solution

1. Step 1: Place both measures on Rows shelf

   Drag Sales and Profit Ratio to Rows to prepare for dual axis.

2. Step 2: Create dual axis and assign mark types

   Right-click Profit Ratio and select 'Dual Axis' to combine. Then set Sales marks to Bar and Profit Ratio marks to Line for clarity.

3. Final Answer:

   Drag Sales and Profit Ratio to Rows, right-click Profit Ratio and select 'Dual Axis', then set Sales marks to Bar and Profit Ratio marks to Line -> Option A

4. Quick Check:

   Dual axis + different marks = clear comparison [OK]

Hint: Dual axis + set different marks for clarity [OK]

Common Mistakes:

• Not setting different mark types for clarity
• Dragging measures to different shelves incorrectly
• Using Tooltip shelf instead of Rows or Columns