Which chart type for what? Bar, line, pie & Sankey
The most common mistake with charts is not the colour or the layout, but the wrong chart type. A pie chart for time trends, or twenty pie slices side by side, confuse more than they explain. This guide gives you clear rules of thumb for which type fits when.
The one question before every chart
Before picking a type, clarify: what should the graphic show? A comparison, a trend over time, a share of a whole, a relationship between two quantities, or a flow between stages? The answer determines the type – not personal taste.
Bar chart: compare categories
The bar chart is the most reliable all-rounder. It suits whenever you compare values across categories – revenue per region, votes per party, sales per product. With many or long category names, horizontal bars read better.
Rule of thumb: sort the bars by size (rather than alphabetically) when the order has no meaning of its own – that makes the comparison clear at a glance.
Line chart: trends over time
As soon as the x-axis is time – days, weeks, months – the line chart is almost always the right choice. The line emphasises development and trends. Several lines compare several series, e.g. revenue across two years. The area chart is a variant that additionally emphasises magnitude.
Pie & doughnut: shares of a whole
Pie and doughnut charts show how a whole (100%) splits into a few parts. They work well with two to five segments. From about seven parts the slices become indistinguishable – then a bar chart is the clearer choice.
- Good: market share of three providers, budget across four items.
- Bad: twenty countries whose shares barely differ.
- Tip: a single highlighted segment directs the eye on purpose.
Sankey: make flows and paths visible
Sankey diagrams show how quantities split from one stage to the next – visitor flows through a funnel, budget flows from sources to items, supply chains from plant to market. The width of each band equals the quantity. They are striking but need data with a clear from-to structure.
Scatter plot: spot relationships
If you want to know whether two quantities are related – say ad budget and revenue – the scatter plot is the tool of choice. Each point is a record; a trend line makes the relationship visible. That reveals patterns hidden in a table.
Scatter plots need real value pairs, so they live in the data dashboard: there the “relationship chart” turns two numeric columns into a scatter plot with a trend line and a correlation value automatically. The Mockup Studio instead focuses on designed bar, line, area, pie, doughnut and Sankey charts.
Try quickly instead of pondering long
Which type works best is often only clear in the picture. In the Mockup Studio you design a chart with your own values and switch the type with a click – ideal for comparing two variants. With real data the data dashboard handles the selection and suggests suitable types directly.
Frequently asked questions
When should I not use a pie chart? With more than about five or six segments, and whenever it is about a trend over time. Bar or line charts are far clearer for those.
What is the difference between a line and an area chart? Both show trends. The area chart fills the space under the line and so additionally emphasises magnitude – useful for cumulative values.
What is a Sankey diagram good for? For flows with a from-to structure: funnels, budget allocation, supply chains. The band width shows the quantity along each path.
All SmashDash tools at a glance
SmashDash brings five free spreadsheet tools together in one place – each runs entirely in the browser, with no upload and no account:
- Turn Excel and CSV into interactive, filterable charts. – Turn Excel and CSV into interactive, filterable charts.
- Design charts with your own values and export them as SVG or HTML. – Design charts with your own values and export them as SVG or HTML.
- Convert Excel, CSV and JSON into XLSX, CSV, JSON, Markdown or HTML. – Convert Excel, CSV and JSON into XLSX, CSV, JSON, Markdown or HTML.
- Remove duplicates and empty rows, normalise number formats. – Remove duplicates and empty rows, normalise number formats.
- Merge, split and compress PDFs and extract tables. – Merge, split and compress PDFs and extract tables.
All processing happens locally in your browser – your files are never uploaded, fully privacy-friendly.