Keep it simple (KISS)
Keep it simple – if there are several relationships in the data and they are not well represented using one chart, separate the data into several charts.
Chart size
The chart should not feel separate from the main content (article or bulletin).
Be consistent
Use the same font type and size for charts as the body font in the surrounding text.
Example of chart using the same font type and size as surrounding text
Unemployed adults age 16 to 64 by region
England, 1993
Example of chart with smaller font than surrounding text
Unemployed adults age 16 to 64 by region
England, 1993
Example of chart with larger font than surrounding text
Unemployed adults age 16 to 64 by region
England, 1993
Number of lines per chart
Number of lines
The maximum number of lines plotted on a chart depends on how similar or different the data are and what you want to highlight.
You need to make sure that each line is easily distinguished from the others.
Example of chart with difficult to distinguish lines and colours
Small multiples solution
Use small multiples if it is difficult to distinguish between the plot lines of four or more similar data sets. Use the same scale for all charts when comparing two or more data series.
Example of small multiples chart
A singular time series of interest can also be highlighted, with all other data sets toned down.
Example of chart using colour and greyscale to show a singular time series
Slope chart solution
Use a slope chart to highlight changes between selected years. The granularity of the data is not evident, however trends are easily noticed.
Example of a slope chart
Location of y-axis
Locate the y-axis on the left or the right of the chart area. Place it on the right if the most recent values are the most interesting or relevant. Otherwise, put it on the left of the chart.
Gridlines and unit intervals
Use gridlines sparingly. There should usually be between four and eight gridlines per chart, depending on the size of the chart and the level of data. They should provide enough reference points to read the data values in the chart easily.
Number of gridlines
Do not use too many or too few gridlines.
Example of too many gridlines
Example of too few gridlines
Example of correct number of gridlines
Gridline intervals
Choose sensible and easy to read and follow gridline intervals.
Example of good gridline intervals
Example of difficult to follow gridline intervals
Gridline colour
Gridlines should always be grey: RGB value (190,190,190).
Example of incorrect use of gridline colour
Gaps between bars
Standard bar chart
A standard bar chart should have gaps between bars that are slightly narrower than the bars. The exceptions to this are the exception of histograms and clustered bar charts.
Example of correct use of gaps between bars
Clustered bar chart
A clustered bar chart should have gaps between the clusters that are slightly wider than a single bar.
Example of correct use of gaps between clustered bars
Borders and backgrounds
Do not use borders and backgrounds for charts.
Example of an inaccessible chart with a background and border
3D and other chart effects
Do not use 3D when creating charts. The false perspective will distort the data.
Example 1
For example, categories A and B seem equal when plotted in 3D. However, category B is noticeably larger, as shown when plotted in 2D.
3D example
2D example
Example 2
When plotted in 3D, the highest value appears to be around 7.9 in 2012. The same data in 2D clearly show the highest value is 8 in 2010.
3D example
2D example
Example 3
In 3D, bar W looks smaller than bar Z. However, they are both equal.
3D example
2D example
We are constantly improving based on research and best practice. Any significant changes to our guidance are available on the Updates page.