How to Choose Chart Colors
Colour is the fastest way to make a chart look professional — and the fastest way to make it unreadable. These are the rules that matter in a business report.
Use as few colours as the chart allows
A single-series chart needs exactly one colour. Giving every bar its own colour implies a grouping that does not exist.
Cap categorical palettes at about five hues. Beyond that, readers cannot reliably match a swatch to a legend entry.
Use one accent colour to highlight the bar or line that your sentence is about, and grey for everything else.
Pick the right palette for the data type
Categorical data needs distinct hues of similar lightness — separate products, regions, channels.
Ordered or quantitative data needs a sequential palette: one hue, light to dark. Ranked bars and heatmaps fall in this group.
Data with a meaningful midpoint needs a diverging palette — two hues meeting at a neutral centre, such as profit versus loss.
Make it accessible
Around 8% of men have some form of colour vision deficiency, so never rely on red versus green alone. Vary lightness as well as hue.
Keep text and thin lines at a contrast ratio of at least 4.5:1 against the background.
Add a second channel wherever you can — direct labels, dash patterns or marker shapes — so the chart still reads in greyscale.
Stay consistent across a report
Lock one colour per entity for the whole document. If Product A is dark blue on page 3, it must be dark blue on page 9.
Prefer muted, desaturated hues for large filled areas and save saturation for small marks and highlights.
FastChart ships five business palettes that already follow these rules, so switching palette keeps the mapping consistent.
Try it with this data
Two series, two lightness steps of the same hue — readable even in greyscale.
Frequently asked
- How many colours should a chart use?
- One per series, up to about five. If you need more, consider splitting the chart or grouping small categories together.
- Should I use gradients in charts?
- Rarely. A gradient across a bar implies a value change along its length that does not exist. Solid fills are almost always clearer.
- What is a colour-blind safe palette?
- One where hues also differ in lightness, so the series remain distinguishable when converted to greyscale or viewed with a colour vision deficiency.
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