'Step' or Matrix Calculations

[RBG]

Here it goes.

Sales %
0-$250,000 0
$250,001-$500,000 15
$500,001-$1,000,000 20
$1,000,001-$2,000,000 25
$2,000,001-$3,000000 30

So I cant figure out the formula that would give me my desired result as
illustrated as follows. If a person sells between 0 and $250k, then don't
apply a percentage, but if that person sells $750k: dont apply a percentage
on the first $250k in sales, 15% on the amount between $250,001 and $500,000
and finally 20% on all sales above $500,001.

Thanks.

 

[Pete_UK]

This link explains how to do it:

http://www.mcgimpsey.com/excel/variablerate.html

Hope this helps.

Pete