Error Bar and Band Charts in Python
When to Use
An error bar chart (also called an error bar plot) shows the uncertainty of
individual estimates, while an error band shades a continuous interval between
bounds. errorbar draws x or y uncertainty around estimates. error_band fills
the region between lower and upper bounds and layers naturally with a line.
Live Demo
Horizontal and Asymmetric Error Bars
Pass a (lower, upper) pair to xerr or yerr for asymmetric uncertainty on
either axis, and use cap_size to draw end caps:
Forecast Fan with Stacked Bands
Layer two error_band marks at different opacities to draw nested forecast
intervals that widen with distance from the last observation:
Chart Types
Error Band
Use error_band for a continuous lower-to-upper interval, commonly layered
beneath a line to show confidence or forecast ranges.
Error Bar
Use errorbar for uncertainty attached to individual observations. It supports
x or y uncertainty and symmetric or asymmetric values.
Variants
Use symmetric or asymmetric error arrays on either axis. Layer a translucent band beneath a line for intervals that vary continuously, or draw capped error bars at selected observations.
Expected Data Shape
errorbar takes x/y estimates plus scalar or array xerr and yerr values.
error_band takes x, lower, and upper arrays of equal length. All inputs may be
named columns resolved through data=.
Key Options
errorbar uses xerr, yerr, cap_size, width, color, and opacity.
error_band uses color, fill, opacity, line_width, line_opacity, and
name.
API Reference
xy.error_band_chart
An uncertainty-band chart composing `error_band` marks.
Props
| Prop | Type | Description |
|---|---|---|
*children | Component | Marks, axes, annotations, and chart chrome. |
title | Optional[str] | Title shown above the plot. |
width | int | str | Chart width in pixels or a CSS size such as ``"100%"``. |
height | int | str | Chart height in pixels or a CSS size such as ``"100%"``. |
padding | Union[float, Sequence[float], None] | Plot margins, as one value or a sequence of side values. Use zero for an edge-to-edge sparkline. |
data | TableLike | Chart-level data used by marks that omit their own ``data``. |
class_name | Optional[str] | CSS class applied to the chart container. |
class_names | Optional[dict[str, str]] | CSS classes keyed by stable chart DOM slot. |
style | Optional[dict[str, StyleValue]] | Inline style overrides for the chart container. |
styles | Optional[dict[str, dict[str, StyleValue]]] | Inline style mappings keyed by stable chart DOM slot. |
on_hover | Optional[Callable[[dict], None]] | Callback receiving hover event payloads. |
on_click | Optional[Callable[[dict], None]] | Callback receiving picked-mark click payloads. |
on_brush | Optional[Callable[[dict], None]] | Callback receiving brush event payloads. |
on_select | Optional[Callable[[Selection], None]] | Callback receiving data-space selections. |
on_view_change | Optional[Callable[[dict], None]] | Callback receiving viewport change payloads. |
hover | Optional[bool] | Whether pointer movement emits hover events. |
click | Optional[bool] | Whether picked marks emit click events. |
select | Optional[bool] | Whether shift-drag box selection is enabled. |
brush | Optional[bool] | Whether brush selection is enabled. |
crosshair | Optional[bool] | Whether plot-aligned hover guides are shown. |
navigation | Optional[bool] | Whether browser pan and zoom navigation is enabled. |
pan | Optional[bool] | Whether plain-drag panning is enabled. |
pan_axes | Optional[tuple[str, ...]] | Declared axis IDs translated by pan gestures. |
zoom | Optional[bool] | Whether viewport zoom is enabled. |
default_drag_action | Optional[DefaultDragAction] | Initial action performed by a plain plot drag. |
zoom_axes | Optional[tuple[str, ...]] | Declared axis IDs changed by zoom gestures and controls. |
zoom_limits | Optional[ZoomLimits] | Minimum and maximum magnification globally or by axis. |
wheel_zoom | Optional[bool] | Whether wheel and trackpad zoom is available. |
box_zoom | Optional[bool] | Whether box zoom is available as a drag action. |
zoom_buttons | Optional[bool] | Whether modebar Zoom In/Out commands are available. |
double_click_reset | Optional[bool] | Whether double-click restores ``reset_axes``. |
reset_axes | Optional[tuple[str, ...]] | Declared axis IDs restored by reset. |
link_group | Optional[str] | Identifier used to synchronize charts in the browser. |
link_axes | Optional[tuple[str, ...]] | Axes synchronized within the link group. |
xy.errorbar_chart
An error-bar chart composing `errorbar` marks.
Props
| Prop | Type | Description |
|---|---|---|
*children | Component | Marks, axes, annotations, and chart chrome. |
title | Optional[str] | Title shown above the plot. |
width | int | str | Chart width in pixels or a CSS size such as ``"100%"``. |
height | int | str | Chart height in pixels or a CSS size such as ``"100%"``. |
padding | Union[float, Sequence[float], None] | Plot margins, as one value or a sequence of side values. Use zero for an edge-to-edge sparkline. |
data | TableLike | Chart-level data used by marks that omit their own ``data``. |
class_name | Optional[str] | CSS class applied to the chart container. |
class_names | Optional[dict[str, str]] | CSS classes keyed by stable chart DOM slot. |
style | Optional[dict[str, StyleValue]] | Inline style overrides for the chart container. |
styles | Optional[dict[str, dict[str, StyleValue]]] | Inline style mappings keyed by stable chart DOM slot. |
on_hover | Optional[Callable[[dict], None]] | Callback receiving hover event payloads. |
on_click | Optional[Callable[[dict], None]] | Callback receiving picked-mark click payloads. |
on_brush | Optional[Callable[[dict], None]] | Callback receiving brush event payloads. |
on_select | Optional[Callable[[Selection], None]] | Callback receiving data-space selections. |
on_view_change | Optional[Callable[[dict], None]] | Callback receiving viewport change payloads. |
hover | Optional[bool] | Whether pointer movement emits hover events. |
click | Optional[bool] | Whether picked marks emit click events. |
select | Optional[bool] | Whether shift-drag box selection is enabled. |
brush | Optional[bool] | Whether brush selection is enabled. |
crosshair | Optional[bool] | Whether plot-aligned hover guides are shown. |
navigation | Optional[bool] | Whether browser pan and zoom navigation is enabled. |
pan | Optional[bool] | Whether plain-drag panning is enabled. |
pan_axes | Optional[tuple[str, ...]] | Declared axis IDs translated by pan gestures. |
zoom | Optional[bool] | Whether viewport zoom is enabled. |
default_drag_action | Optional[DefaultDragAction] | Initial action performed by a plain plot drag. |
zoom_axes | Optional[tuple[str, ...]] | Declared axis IDs changed by zoom gestures and controls. |
zoom_limits | Optional[ZoomLimits] | Minimum and maximum magnification globally or by axis. |
wheel_zoom | Optional[bool] | Whether wheel and trackpad zoom is available. |
box_zoom | Optional[bool] | Whether box zoom is available as a drag action. |
zoom_buttons | Optional[bool] | Whether modebar Zoom In/Out commands are available. |
double_click_reset | Optional[bool] | Whether double-click restores ``reset_axes``. |
reset_axes | Optional[tuple[str, ...]] | Declared axis IDs restored by reset. |
link_group | Optional[str] | Identifier used to synchronize charts in the browser. |
link_axes | Optional[tuple[str, ...]] | Axes synchronized within the link group. |
FAQ
How do I add error bars to a chart in Python?
Add an xy.errorbar(x, y, yerr=...) mark (use xerr for horizontal error) to
turn any chart into an error bar graph; it supports symmetric or asymmetric
values and optional caps.
What is the difference between an error bar and an error band?
An error bar shows uncertainty at individual points; an error band fills a continuous lower-to-upper region, usually layered beneath a line for confidence or forecast intervals.
How do I draw a confidence interval band in Python?
Use xy.error_band(x, lower, upper) and layer xy.line(x, estimate) on top so
the shaded interval sits behind the trend line.
Can error bars be asymmetric?
Yes. Pass separate lower and upper magnitudes to yerr (or xerr) to draw
different error distances above and below each point.