In this lesson you can learn how to use trendlines in Excel.

Trendlines are useful when you present data changing over time. The trend line on the chart is also used to predict the distribution of the data in the future or the past. Forecasting is used in statistics and econometrics, where it is called regression.

Trendlines in Excel can be added only into uncumultive and two-dimensional charts. Types of graphs, which can be used to: area, column, line, stock, bar, scatter and bubble. Trend lines can not be added to the chart: three-dimensional, stacked and radar, pie, surface and ring.

I created a simple line chart as an example.

Trendlines Example Line Chart

To add a trend line, first you need to click on the chart. On the ribbon, there is a new Chart Tools menu. In the Layout tab, you'll see the Trendline button. You can insert 4 different types of trend lines. These are: Linear Trendline, Exponential Trendline, Linear Forecast Trendline and Two Period Moving Average.

Linear Trendline for this sample line chart will be like in the picture below.

Linear Trendline

In this way, you can insert a very simple trendlines. You get more opportunities after selecting More Trendline Options button.

More Trendline Options

Then appears Format Trendline dialog box.

Format Trendline

This dialog box gives you a lot of options to work with trendlines. For example, let's see how it will look next 10 Forward Forecast periods for your sample trendline.

Trendline sample line chart forward trend

It's just a very simple example.

As you can see, the trendlines are pretty useful tool.