Chart Bars or Columns that change color based on data values.

First remember that an Excel BAR Chart has a horizontal orientation, while an Excel COLUMN chart has a vertical orientation.

Suppose we have some simple data like this:
[tt]
Region Budget
North 200
South 400
East 600
West 800
[/tt]
and you want to display any Budget amount in the chart less than 500 as RED and all other amounts as GREEN.

First we need to condition the data to reflect this requirement:
[tt]
A B C D
1 Region Budget RED GREEN
2 North 200 =IF(B2[red]<[/red]500,B2,0) =IF(B2[red]>=[/red]500,B2,0)
3 South 400
4 East 600
5 West 800
[/tt]
The result, when you copy the formulas down thru all rows of data:
[tt]
Region Budget RED GREEN
North 200 200 0
South 400 400 0
East 600 0 600
West 800 0 800
[/tt]
Now you create your chart, using only columns C & D (RED & GREEN) for data and column A for labels. Use the STACKED Bar or Column feature