Axes

The Axes section in the Style tab controls the appearance and behavior of the X axis and Y axis (or left and right Y axes in dual-axis charts). Most axis settings are available for all Vega-based chart types (bar, line, area, scatter, heatmap).

X axis

Setting	Description
Show axis	Toggle the X axis on or off
Title	Custom axis label — leave blank to hide the axis title
Grid lines	Toggle grid lines perpendicular to the X axis
Labels	Toggle axis tick labels
Label angle	Rotate axis labels (useful for long category names)
Label format	Number or date format applied to axis labels

Y axis (left)

Setting	Description
Show axis	Toggle the Y axis on or off
Title	Custom axis label
Grid lines	Toggle horizontal grid lines
Labels	Toggle axis tick labels
Label format	Number format applied to axis labels (e.g. $,.0f for currency)
Min / Max	Override the axis scale minimum and maximum values

Dual Y axis (right axis)

Add a second Y axis on the right side of the chart to plot a series on a different scale. This is useful for combining measures with different units or magnitudes — for example, showing order count on the left axis and average order value on the right.

To use the right axis:

1. In the Series configuration for a specific series, change the Y axis assignment from Left to Right.
2. The right axis settings appear in the Style tab — configure its title, labels, and scale independently from the left axis.

Reference lines

Add horizontal reference lines to mark a target, threshold, or benchmark value. Reference lines appear at a fixed Y value across the full width of the chart.

To add a reference line:

1. In the Y axis section of the Style tab, click Add reference line.
2. Set the Value — the Y position of the line.
3. Optionally set a Label that appears next to the line.
4. Configure Color and Style (solid, dashed, or dotted).

You can add multiple reference lines to the same axis. Each is configured independently.

<Note> Reference lines are only available on the left Y axis. For right-axis reference lines, use a [custom Vega-Lite spec](/docs/explore-analyze/charts/chart-types/custom). </Note>