Trying to extract the best amount necessary to withdraw from a bank account that results in bank account balance of 0. One fee is constant for withdrawal while the other depends on the initial withdrawal amount. Once both are added to withdrawal amount should be equal to bank account balance.

Public conversionCost As Double = 0.035 Public atmFee As Double = 3.15   'Calculates the maximum amount you can withdraw from current balance Public Sub FullDraw(ByVal flFee As Double, actBal As Double, excRate As Double)      Dim withdrawalAmt As Double      'redact atmfee first from current balance     withdrawalAmt = actBal - atmFee       'Loop until figures match to find the perfect withdrawal amount that doesn't     'leave money behind      Dim totalAmt As Double      Do Until totalAmt = actBal          withdrawalAmt -= 1          'calculate possible converison fee so it can be included         Dim conversionFee As Double = conversionCost * withdrawalAmt          'add fee          totalAmt = withdrawalAmt + conversionFee      Loop      Label3.Text = withdrawalAmt * excRate  End Sub