Data bars allows you to insert a data bar into each cell in the selection, the size is based on the cell value. The biggest data bar corresponds to the largest value in selection.

How to build

1. Select cells.
2. Go to tab "Home" on the ribbon.
3. Press with left mouse button on the "Conditional Formatting" button.
4. Press with left mouse button on "Data Bars".
5. Choose between "Gradient Fill" or "Solid Fill", pick a data bar color to create data bars.
   
   (Press with left mouse button on to expand image)

How to customize data bars

If you want to change data bars settings for an existing cell range follow these steps:

1. Select the cell range.
2. Go to tab "Home" on the ribbon.
3. Press with left mouse button on "Conditional formatting" button.
4. Press with left mouse button on "Manage Rules..."
   
5. Press with left mouse button on "Edit Rules..."
   

To create new data bars and also edit settings before creation then follow these steps:

1. Select cells.
2. Go to tab "Home" on the ribbon.
3. Press with left mouse button on the "Conditional Formatting" button.
4. Press with left mouse button on "Data Bars".
5. Press with left mouse button on "More Rules..."
   

The data bar settings dialog box appears.

This dialog box lets you format the data bars and how the minimum and maximum values are calculated. You can also hide the values so only the data bars are visible.

I prefer having the values next to the data bars, simply copy the values and paste to the next column then apply the data bars with values hidden.