calculate interest for one-time payment on loan

[ken <gebser speakeasy net>]

Hi, people,

This should be a simple thing to do.  I'm surprised there's not a
function for it.  Or maybe there is one.  I've looked at the FAQ, read
through quite a few of the functions, and searched the archives for this
list and haven't found what I need.  As my Subject line says, I'm
looking for a way to calculate interest for one-time payment on loan.
Too simplistically, it's this:

InterestAmt = DailyInterestRate * NumberOfDays

DailyInterestRate = AnnualInterestRate / 365

NumberOfDays(DateStart, DateEnd)

Gnumeric is nice because variables such as the above can be hardcoded
into a formula or fetched from a cell.  I could hardcode everything but
DateEnd; that needs to be fetched from a cell.

Anyone know a way to do this?


tnx much,
ken

-- 
"The mark of a moderate man is freedom from his own ideas.
Tolerant like the sky all-pervading like sunlight, firm like a
mountain, supple like a tree in the wind, he has no destination
in view and makes use of anything life happens to bring his
way." -- Tao Te Ching