Please Note: This article is written for users of the following Microsoft Excel versions: 2007, 2010, 2013, 2016, 2019, and Excel in Office 365. If you are using an earlier version (Excel 2003 or earlier), this tip may not work for you. For a version of this tip written specifically for earlier versions of Excel, click here: Smoothing Out Data Series.

Smoothing Out Data Series

by Allen Wyatt
(last updated May 8, 2020)

4

When you create line charts in Excel, the lines drawn between data points tend to be very straight. (This makes sense; the lines are meant to connect the points.) You can give your graphs a more professional look by simply smoothing out the curves Excel uses at each data point. Follow these steps if you are using Excel 2007 or Excel 2010:

  1. In your chart, right-click on the data series that you want to smooth. Excel displays a Context menu.
  2. Choose Format Data Series from the Context menu. Excel displays the Format Data Series dialog box.
  3. Click Line Style at the left side of the dialog box. (See Figure 1.)
  4. Figure 1. The Line Style options of the Format Data Series dialog box.

  5. Select the Smoothed Line check box.
  6. Click on OK.

The steps are slightly different in Excel 2013 and later versions:

  1. In your chart, right-click on the data series that you want to smooth. Excel displays a Context menu.
  2. Choose Format Data Series from the Context menu. Excel displays the Format Data Series task pane at the right side of the screen.
  3. Click the Fill and Line icon (it looks like a spilling paint can).
  4. Click Line to make sure the line options are visible. (See Figure 2.)
  5. Figure 2. The Line options of the Format Data Series task pane.

  6. Select the Smoothed Line check box, which is at the very bottom of the options.
  7. Click on OK.

One final note: Just because Excel provides a way for you to smooth the lines connecting data points, that doesn't always mean that you should. Make sure you give some thought to what conclusions people may draw from your data. If the data in the chart is more precise with unsmoothed lines, then you should probably not smooth them. You want to avoid misrepresenting your data or causing readers to draw incorrect conclusions.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (9510) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, and Excel in Office 365. You can find a version of this tip for the older menu interface of Excel here: Smoothing Out Data Series.

Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He is president of Sharon Parq Associates, a computer and publishing services company. ...

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Comments

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What is three more than 4?

2020-05-13 17:15:15

Alex

Hi Alan,

Thanks for the tips!
I have 2 line graphs in my PPT on consecutive pages. On the 1st I can edit the data point, thus change the data series to smooth the line but on the 2nd graph, the "Line Styl" option does not show. Can you explain why and how I can smooth that graph? Thanks, Alex


2020-05-08 10:52:01

Dave Bonin

If you have a lot of jagged points, a smoothed line may give you little more than a sketch of a really nasty roller coaster.

In that case, here's an alternative.
- Plot two series on the same chart:
- Use a scatter plot to plot each point individually, with no line connecting the points.
- Then add a line chart to plot the averages of several adjacent points. Do this for each possible grouping of x adjacent points. This will give a smoothed line and it will allow the readers to see how much scatter there is in the data. I generally use an odd number of points. Three, five or seven works well.

Another alternative would be to calculate a polynomial regression line and chart that through a scatter plot of your points. One caution, though... Remember that the regression line is really only valid over its calculated range. In other words, be very careful using it to extrapolating beyond your data.


2016-04-25 16:04:17

Nahid

Thank you very much. You may have just saved me from having to use a seperate plotting program to produce some transit light curves :).


2014-04-14 08:24:58

Bryan

It's good that you cautioned against using smoothed lines, but I think my previously-deleted comment provides even greater insight:

I think more important than *how* to do it is *when* to do it, and that answer is: almost never. If your graph represents descrete measurements, you should never smooth as this implies a pattern where you haven't measured one (depending on the measurements, you shouldn't always even have a line). If your graph only describes part of a continuous function (like plotting a sine curve), then it's safe to use smoothing, as long as you realize its limitations.

Jon Peltier has a lot to say on this topic:
* http://peltiertech.com/WordPress/smooth-talking-lies/
* http://peltiertech.com/WordPress/plotting-measured-data/


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