# How to Add a Trendline in Excel – Full Tutorial (2024)

On a graph, it can be hard to find the actual direction of a data series if there is no line on the graph to show the pattern of the data series.

But there’s a tool to help us out with that: the trendline📈

You can even use the trendline to get the expression of the data points, so you can do forecasts.

Grab the sample workbook here and let’s dive into adding a trendline to this dataset🤿

## How to add a trendline in Excel

To start the lesson, we will first convert our dataset to a chart.

I am creating a scatter plot for the example data set.

You can add trend lines to any of the below chart types👍

But, we can’t add a trendline to every chart type. The below chart types are not supporting the trendline👎

• Pie chart
• Surface chart
• Stacked chart
• Sunburst chart
• Doughnut chart

Let’s add a trendline to the above chart.

1. Select the chart.

Click on the chart to select the chart.

1. Click the plus (+) button in the top right corner of the chart to expand the chart elements.
1. Select trendline from chart elements.

Our chart is quickly updated with a linear trendline.

1. Double-click on the trendline to open the format trendline pane.
1. Select one of the 6 trendline options.
• Exponential trendline
• The exponential trendline is a curved line and this trendline is helpful when data values increase or decrease at a constant rate.
• An exponential curve cannot be generated if the data set has negative values and zeros.
• Linear trendline
• A linear trend line is suitable when data points increase or decrease at a steady rate.
• Logarithmic trendline
• The following equation is used to compute the least squares fit of the data points.
• A logarithmic trendline can have both negative and positive values.
• Polynomial trendline
• The following equation is the polynomial equation to calculate the least squares fit of the data points.
• Power trend line
• The power trendline is a curved line.
• It cannot be used in any of the data values that are negative or zero.
• Moving average trendline
• The moving average trendline clearly shows a trend in the data set by smoothing away variations in the data.
• We can change the number of periods to find the average values for the trendline.

The name of the selected trendline option is displayed in the format trendline pane🔎

### Linear trendline

Let’s apply a linear trendline to our data set.

Select “Linear” from the trendline options.

The equation below is used to determine the least squares fit for a line in a linear trendline:

### Polynomial trendline

Let’s use the polynomial trendline for our data values.

Select “Polynomial” from the trendline options.

In the order box, we can enter a whole number between 2 and 6.

The number of bends (hills and valleys) in the curve can be used to estimate the polynomial’s order⛰️⛰️⛰️

Typically, there is only one hill or valley on an Order 2 polynomial trendline.

Order 3 contains one or two hills or valleys.

Order 4 typically has three or more.

Our chart with the polynomial trendline is ready.

Pro Tip!

You can add multiple trendlines on the same chart😍

How to add a trendline to each data series in the same chart?

Select one data series at a time and follow the steps of the above example.

How to add different types of trendlines for the same data series?

Repeat the steps of the above example and choose a different trendline each time.

Let’s add different trendlines to our example.

The red line is the linear trend line and the black line is the polynomial trend line.

## Show trendline equation

Select the checkbox of “Display equation on chart” to add trendline equations on the chart.

If this option is selected, Excel displays the R-squared value on the chart.

And you can see it here:

Go to the Fill & Line section of the format trendline pane to change the line color of the trendline.

## What is a trendline?

A trendline can be a line or curve to show the direction of data values.

It helps to visualize the pattern of a data series more effectively and easily.

It helps to forecast future trends more accurately and very quickly.

The trendline is very useful to get a quick insight into our data👌

For example, an increasing slope of a trendline indicates a positive correlation between the two variables. If the slope decreases, it indicates there is a negative correlation between the two variables.

Trendline reliability is depending on the R-squared value of the data set.

It assesses how well the linear regression line fits the data.

R squared value is ranging between 0% and 100%.

If the R squared value is 100%, the line fits the data values 100%.

It means that the independent variable completely explains the dependent variable.

When the R-squared value is closer to 100% the trendline is more reliable.

A low R-Squared value indicates that the trendline is not reliable.

## That’s it – Now what?

You now understand how simple it is to insert a trendline in an Excel chart.

Did you tag along in the sample workbook?

Well done💪🏼

So, you’re looking to add a trendline to a chart.

But what data does your chart display?

It better be something useful.

The best functions for getting useful numbers in Excel are: IF, SUMIF, and VLOOKUP.

If you’re not already an expert on those topics, you should sign up for my 30-minute free online course and learn them all, step-by-step.

## Other resources

If you like to learn more about creating Excel charts, you can read our articles about how to create a scatter plot, a line graph, or a column chart.

Also, closely related to trendlines is forecasting in Excel. Read all about it here or dive into linear regression specifically.