Data Visualization Snippets — Free HTML CSS JS No-Library Chart & Data Viz Examples

Most product charts do not need a charting library. A bar chart is rectangles, a line chart is a path, a donut is a stroked circle — and drawing them yourself means full control over styling, animation and accessibility, with nothing added to your bundle.

These snippets cover the common chart types plus the small-format marks that dashboards actually run on: sparklines, progress rings, heatmap grids, gauges and metric tiles with trend indicators.

A chart is simpler geometry than it looks

A bar chart is a set of rectangles whose heights are derived from a linear scale mapping data values to pixels. A line or area chart is one SVG path whose points come from mapping each data point through the same kind of scale on both axes. A donut is a circle with stroke-dasharray used the same way it draws a progress ring. Seeing the charts this way — as a small number of well-understood primitives with data-derived coordinates — is what makes hand-drawing them tractable instead of intimidating.

Deriving scale from data, not assuming it

Every chart here computes its axis domain from the actual data range at render time rather than hard-coding fixed minimum and maximum values. That single habit is what lets the same rendering code handle a dataset that later grows or shrinks, and it is the entire mechanism by which "connect this to real data" reduces to swapping one array at the top of the file.

Small-format marks carry dashboard density

A sparkline, a trend arrow, and a metric tile with a delta communicate more information per pixel than a full chart with axes and a legend, which is why dashboards lean on them heavily. These marks use the same scale-and-path logic as the full-size charts, just sized down and stripped of axis chrome, so the two categories share a real implementation rather than being built from separate techniques.

Accessibility is a second representation, not an attribute

A chart with role="img" and a label is a start, but the numbers behind it still need to reach a screen reader — which means providing the underlying data as a visually hidden table or a toggleable data view alongside the visual. A chart with no textual equivalent conveys nothing to anyone who cannot see it, no matter how well the visual itself is built.