How to use a logarithmic scale

When to use a logarithmic scale

Logarithmic scales are extremely useful but not always understood. They show relative values instead of absolute ones, on an exponential scale.

There are two main reasons to use logarithmic scales in charts and graphs. The first is to respond to skewness towards large values; meaning cases in which one or a few points are much larger than the bulk of the data. The second is to show percent change or multiplicative factors – to show a growth rate, for example. 

Because log scales never reach zero, you can easily spot them in use by checking the y axis.

How to apply a logarithmic scale in Flourish

In Flourish, you can use logarithmic scales on your charts made in either the Line, bar & pie template, or the Scatter template.


Under X axis or Y axis in the settings panel, find the section called Scale. Here, you'll see buttons to switch between Linear and Log scales.


In our Line, bar, pie template, you can also add a user-facing control for scales, allowing the user to switch between Linear and Log themselves. 

Under Controls & filters, enable Show log control for Y axis.