sparklines

Sparklines are tiny inline charts that fit within text or a small region of a page, used to illustrate the pattern or trend of a data series without taking much space. They typically display a single variable over a defined period and intentionally omit axes, labels, and gridlines, focusing on the overall shape of the data.

Common variants include line sparklines, bar sparklines, and win/loss sparklines. Line sparklines show continuous values, bar sparklines render positive and negative or positive values as vertical bars, and win/loss sparklines depict only the sign of changes (up or down).

Historically, sparklines were discussed by Edward Tufte and later widely implemented in spreadsheet software. They are now supported in Excel, Google Sheets (SPARKLINE function), and many business intelligence tools. They are used in dashboards, performance reports, and inline data tables to provide immediate visual context beside numbers.

Design considerations include choosing a consistent scale when comparing multiple sparklines, ensuring color choices convey meaning (e.g., green for positive), and providing context when values differ widely from one sparkline to another. Because they lack axes, sparklines are not suitable for precise comparisons or datasets with heterogeneous scales; they should be paired with supporting text or headers. Accessibility can be improved with descriptive alt text.