## Related Tutorials

Excel > Excel 2007 Intermediate > Charts

# Adding a Trendline to a Chart

A trendline shows the trend of values by averaging out high and low points. It can also be used to predict future values.

There are 6 different trendlines available in Excel, and it is important to choose the best type to show an accurate trend in your values.

Trendline

When Used

Linear

Used for values that increase or decrease at a steady rate

Logarithmic

Used for values that increase or decrease quickly before levelling out

Polynomial

Used for values that fluctuate

Power

Used for values that increase or decrease at a specific rate

Exponential

Used for values that increase or decrease at increasingly higher rates

Moving Average

Averages out the high and low points smoothing any fluctuations

The accuracy of a trendline is recognised by its R-Squared value. The R-Squared value is a number from 0 to 1. The closer to 1 the value is, the more accurate the trendline. The R-Squared value can be displayed on the chart.

1. Select the chart
2. Click the Layout tab under Chart Tools on the Ribbon
3. Click Trendline from the Analysis group
4. A list of trendlines to choose from is displayed. Select the trendline that accurately plots your data.
5. If the trendline that you want is not shown in the list, click More Trendline Options

6. If you are using more than one data series, a box will appear asking you which series to base the trendline on
7. Select the trendline type from the options provided
8. When using a Polynomial trendline you should set the Order, which is how many bends the trendline will have. Order 2 has 1 bend, order 3 has 2 and so on.

For Moving average trendlines you should set the Period, which is the number of values to average into a point on the trendline.

9. Click the display R-Squared value on chart checkbox
10. It is also possible to predict future values by using the forecast pane and to customise the legend entry using the Trendline Name pane

11. Click Ok

You can add more than one trendline to a chart and format a trendline following the same procedure as formatting any other chart element.

To remove a trendline, select the trendline and press Delete.