Gauge Charts: Best Practices and Examples

Gauge charts are tools that indicate a single value within a predefined scale.

When you visit a website to check your internet speed, you’ll likely come across an information panel where a needle moves until it reaches the speed indicator.

That’s a gauge chart, an indispensable mechanism in several fields, the most common being speed measurement, but it can also be used to measure various types of data, such as temperature. Keep reading to learn more about how it works, best practices, and application examples.

What are gauge charts

Gauge charts are used when there’s a need to identify a single value on a predefined scale. In other words, they serve to measure the rate of change relative to defined targets.

The most common representation is circular or semicircular, with a needle that moves according to the gauge’s reading. However, they can also appear in other formats, such as bars (horizontal) and columns (vertical).

These needles indicate information much like reading a dial. The value each needle points to corresponds to a number or indicator that can be easily interpreted based on its intervals.

Generally, these intervals are key indicators within a range of values. Going back to the internet example, let’s say the chart’s maximum speed is 100 Mbps (the upper limit of the value range).

If the needle moves to 75 Mbps, that indicator has shown its result in a simple way, and anyone can understand that the speed is 75 Mbps.

Besides values, gauge charts can also display specific color codes, usually the same ones found in traffic lights, where green is normal, yellow calls for attention, and red can indicate a critical state. However, these colors can vary depending on the chart’s purpose.

The following information must be present in gauge charts:

• Measurement – represents the series used for measurement;
• Target – represents the defined numeric field and its unit of measurement;
• Animation – represents the movement of the needle or other indicator, serving as a cue for the measurement.
  
  

When should I use a gauge chart

The applications of gauge charts vary depending on their type; here are the two most commonly used:

• Dial chart (circular or semicircular)
  
  

This type of gauge chart allows information to be displayed clearly. The needle sits at a central point and moves from the smallest to the largest scale of the unit of measurement, showing data in a regular way.

The outer scale is commonly color-coded to provide additional performance information.

Main applications: speedometers, temperature gauges, volume, pressure, etc.

• Bar chart (horizontal) and column chart (vertical)
  
  

As the name suggests, these charts have horizontal and vertical layouts to make them easier to understand. The information is distributed linearly, from the smallest to the largest scale.

Main applications: thermometer, volume measurement (decibels), etc.

What are the main guidelines for creating gauge charts

Since gauge charts are quite simple, there are few rules to follow:

• Linear – It must be linear, meaning it goes from one point to another with logical and realistic intervals;
  
  
• Measurement – It can only measure one factor per chart and display a single unit of measurement;
  
  
• Unit of measurement – It should start from zero or from a point considered the starting point for that measurement. If it’s a percentage measurement, the end point will be 100%.
  
  
• Colors – There should be a logic to them; the ranges generally represent performance levels, such as satisfactory, average, and unsatisfactory.
  
  

What are the advantages of gauge charts?

The main advantage of gauge charts is how easy they are to understand. They measure only one element, the values are simple to identify since they generally go from smallest to largest, plus the color coding is intuitive and immediately interpretable.

The most common examples are speedometers, but there’s a wide range of applications, especially in industry.

Without a doubt, this is one of the most widely used chart types since its earliest versions. It’s often used to compare values or show an increasing or decreasing trend.

If you need to report your resources for completing a task during a meeting, this chart can help a lot. It displays columns with sizes proportional to the values they represent.

Now that you know everything about gauge charts, check out our solution to further improve your business’s data management.