I am sure I’m missing something here, but I don’t understand why making bullet charts and boxplots have to be so overly complex in Excel. Instead of messing around with bars and scales and secondary axes, a 1D scatterplot can be used to make both charts. I’ve been using this (obvious?) solution for a long time. I’m sure it is not original (I’m not that good…), but I though I could share it, since I couldn’t find anyone sharing it.

The bullet chart comes with a bonus:

bullet chart in Excel

And this is a regular boxplot, including the outliers:

boxplot in Excel

In both cases you can have multiple charts using the same scatterplot.

And here is the file for you to explore. It was made in Excel 2013. If you think there are easier ways to make these charts in Excel please share them in the comments below.