day zero you owe £10
14 days from now you will owe 10*(1+1%)
28 day from now you will owe 10*(1+1%)*(1+1%) = 10*(1+1%)^2
42 day later 10*(1+1%)^3
In 90 days you will owe 10*(1+1%)^(90/14)

Just think back to those fun arithmetic classes.
best wishes
--
Bernard V Liengme
Microsoft Excel MVP
www.stfx.ca/people/bliengme
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"spudsnruf" wrote in message
...
I borrow money for my small biz on an indefinite period., and I cant get
the
answer I need bu usng Excel 2003's interest rate calculations, as this
seems
to only work if there is a defintie period of time.
example:

I borrow £10 at a rate of 1% for every 14days.
Typically I repay it at anytime between 14 and 90 days.
So i want to be able to know how much interest I am clocking up on 14 day
basis.

Advice always welcome!
Thank you