>I have an application that currently uses the following formula for calculating the margin on an item sold:
>
>lnMargin = ROUND((1-(tnCost/tnPrice)) * 100,1)
>
>The problem is that we have customers entering tncost > tnPrice to create a negative margin/loss leader situation. In this case, the returns from the function are huge and cause an overflow.
>
>Can someone tell me or show me a formula that will calculate negative margins correctly?
>
>Thanks..

I'm not familiar with (negative) cost margins, but generally speaking I would test for the relative cost/price and use an appropriate formula. E.g.:

IF tnCost <= tnPrice
    lnMargin = ROUND((1-(tnCost/tnPrice)) * 100,1)
ELSE
*   Put a suitable formula here
*   ( or tell them negative margins are not allowed? )
ENDIF

Bill

William A. Caton III
Software Engineer
MAXIMUS
Atlanta, Ga.