I am trying to create an excel formula for the following scenario:

If the subtotal (ie E74) is 100,000 or less = 6% of E74. If the subtotal
is over 100,000, 6% on the first 100,000, 4% on the next 400,000 and 2% above
500,000.

Can anyone help? This is a bit out of my league.

Thanks!