Sparklines are small, intense, word-sized data graphics invented by Edward Tufte. They show the trend or pattern of a data series without axes, labels, grid lines, or other chart adornments — communicating the shape of data in a glance.
A sparkline might show a stock's price history over the past year in a space the size of a word, embedded directly in a paragraph of text or alongside a numerical value in a table. The viewer perceives the trend without leaving the surrounding context or consulting a separate chart.
Typical uses:
- Trend columns in tables — each row's metric accompanied by a tiny history line
- Dashboard KPIs — current value plus miniature history
- Inline data in reports — prose that describes trends alongside mini-visualisations
- Mobile-friendly displays where full charts don't fit
Key design principles:
- Tiny (roughly the height of a line of text)
- Minimal (no axes, labels, or titles — the surrounding context provides them)
- Contextual (placed near the number or word they describe)
- Consistent scale across related sparklines for valid comparison
- Highlighted points (markers for min/max, current value) when useful
Sparklines exploit the data-ink principle extremely: nearly 100% of the graphic is data. They pack information density without demanding separate viewing. Modern spreadsheets, dashboard tools, and programming libraries (D3, Matplotlib, ggplot) all support sparklines natively.
Related terms: Data-Ink Ratio, Small Multiples, Dashboard Design
Discussed in:
- Chapter 14: Data Visualisation — Tufte's Principles
Also defined in: Textbook of Usability